LOOMIS SAYLES INVESTMENT TRUST, 497, 1998-04-24

LOOMIS SAYLES INVESTMENT TRUST
497, 1998-04-24

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<PAGE>

LOOMIS SAYLES INVESTMENT TRUST

LOOMIS SAYLES CALIFORNIA TAX-FREE INCOME FUND

ONE FINANCIAL CENTER
BOSTON, MASSACHUSETTS 02111
(617) 482-2450

PROSPECTUS

APRIL 22, 1998

The Loomis Sayles Investment Trust (the "Trust") is a group of seven mutual
funds including the Loomis Sayles California Tax-Free Income Fund (the "Fund").
The other series, which are described in separate prospectuses, are:

Loomis Sayles Core Fixed Income Fund
Loomis Sayles Core Growth Fund
Loomis Sayles Fixed Income Fund
Loomis Sayles High Yield Fixed Income Fund
Loomis Sayles Intermediate Duration Fixed Income Fund
Loomis Sayles Investment Grade Fixed Income Fund

Except for the Fund, the funds are designed specifically for tax-exempt
investors such as pension plans, endowments and foundations, although other
institutions and high net-worth individuals are eligible to invest. Each of the
funds is separately managed and has its own investment objective and policies.
Loomis, Sayles & Company, L.P. ("Loomis Sayles") is the investment adviser of
each of the funds.

This Prospectus concisely describes the information that you should know
before investing in the Fund. Please read it carefully and keep it for future
reference. A Statement of Additional Information dated April 22, 1998 is
available free of charge; to obtain a free copy or to make any inquiries about
the Fund write to Loomis Sayles Investment Trust, One Financial Center, Boston,
Massachusetts 02111 or telephone (617) 482-2450. The Statement of Additional
Information, which contains more detailed information about the Fund, has been
filed with the Securities and Exchange Commission (the "SEC") and is
incorporated by reference into this Prospectus.

THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES
AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE
SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED
UPON THE ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE
CONTRARY IS A CRIMINAL OFFENSE.
<PAGE>

<TABLE>
<CAPTION>
TABLE OF CONTENTS
<S> <C>
SUMMARY OF EXPENSES............................................ -3-

FINANCIAL HIGHLIGHTS........................................... -4-

PRIOR PERFORMANCE.............................................. -5-

THE TRUST...................................................... -6-

INVESTMENT OBJECTIVE AND POLICIES.............................. -6-

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS.................. -7-

THE FUND'S INVESTMENT ADVISER.................................. -9-

FUND EXPENSES.................................................. -10-

PORTFOLIO TRANSACTIONS......................................... -10-

HOW TO PURCHASE SHARES......................................... -10-

HOW TO REDEEM SHARES........................................... -11-

OTHER INFORMATION.............................................. -11-

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES................ -11-

APPENDIX....................................................... A-1
</TABLE>

2
<PAGE>

SUMMARY OF EXPENSES

The following information is provided to assist you in understanding the
various costs and expenses that, as an investor in the Fund, you will bear
directly or indirectly. The information is based on expenses for the Fund's
fiscal year ended December 31, 1997. The information below should not be
considered a representation of past or future expenses, as actual expenses may
be greater or less than those shown. Also, the assumed 5% annual return in the
example should not be considered a representation of investment performance, as
actual performance will depend upon the actual investment results of securities
held in the Fund's portfolio.

Shareholder Transaction Expenses:
Maximum Sales Load Imposed on
Purchases (as a percentage of offering price) none
Maximum Sales Load Imposed on
Reinvested Dividends (as a percentage of
offering price) none
Deferred Sales Load (as a percentage of original
purchase price or redemption
proceeds as applicable) none
Redemption Fees (as a percentage of amount
redeemed) none
Exchange Fees none

Annual Fund Operating Expenses
(as a percentage of average net assets):
Management Fees (after expense
limitation) .50%
12b-1 Fees none
Other Operating Expenses (after expense
limitation)/1/ .15%
Total Fund Operating Expenses (after
expense limitation)/1/ .65%

Example
You would pay the following
expenses on a $1,000 investment
assuming a 5% annual return
(with or without a redemption at
the end of each time period):

One Year $7
Three Years $21
Five Years $36
Ten Years $81

3
<PAGE>

FINANCIAL HIGHLIGHTS

The financial highlights table that follows is for the period March 7, 1997
through December 31, 1997. The following information should be read in
conjunction with the financial highlights, financial statements, and notes
thereto that have been audited by Coopers & Lybrand, L.L.P., independent
accountants, whose report thereon appears in the Fund's 1997 Annual Report,
which is incorporated by reference into this Prospectus and the Statement of
Additional Information.

<TABLE>
<CAPTION>
March 7+ through
December 31, 1997
-----------------
<S> <C>
Net asset value, beginning of period......................... $ 10.17

Income from investment operations -
Net investment income....................................... 0.31
Net realized and unrealized gain (loss) on investments...... 0.36
--------
Total from investment operations.......................... 0.67

Less distributions -
Dividends from net investment income........................ (0.40)
Distributions from net realized capital gains............... (0.03)
--------
Total distributions....................................... (0.43)
--------
Net asset value, end of period............................... $ 10.41
========

Total return (%)............................................. 6.7**
Net assets, end of period (000).............................. $16,822
Ratio of operating expenses to average net assets (%)........ 0.65*
Ratio of net investment income to average net assets (%)..... 4.58*
Portfolio turnover rate (%).................................. 15.9**
Without giving effect to the voluntary expense limitations:
The ratio of operating expenses to average net assets
would have been (%)........................................ 1.46*
The net investment income per share would have been......... $ 0.26
</TABLE>

+Date of effectiveness of the Fund's registration statement under the
Securities Act of 1933, as amended.
*Annualized.
**Not annualized.

Further information about the performance of the Fund is contained in the
Fund's semiannual and annual reports to shareholders, copies of which may be
obtained without charge by writing or telephoning the Trust at the address and
telephone number stated on the cover of this Prospectus.

4
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PRIOR PERFORMANCE

(FOR A SHARE OF THE FUND OUTSTANDING THROUGHOUT THE INDICATED PERIODS)

The information presented below, for the periods indicated, relates to
periods prior to the effectiveness of the Fund's registration statement under
the Securities Act of 1933, as amended (the "1933 Act"). The following
information should be read in conjunction with the financial highlights,
financial statements, and notes thereto that have been audited by Coopers &
Lybrand, L.L.P., independent accountants, whose report thereon appears in the
Fund's 1997 Annual Report, which is incorporated by reference into this
Prospectus and the Statement of Additional Information. The Fund is managed in
a manner that is in all material respects similar to the manner in which it was
managed prior to the effectiveness of its registration statement under the 1933
Act.

January 1, 1997 Year Ended June 1* through
through March 6, December 31, December 31,
1997 1996 1995
---------------- ------------ ---------------
<S> <C> <C> <C>
Net asset value, beginning of period.................... $ 10.19 $ 10.23 $ 10.00

Income from investment operations -
Net investment income................................... 0.16 0.46 0.26
Net realized and unrealized gain (loss) on investments.. (0.11) (0.04) 0.23
------- ------- --------
Total from investment operations...................... 0.05 0.42 0.49
------- ------- --------

Less distributions -
Dividends from net investment income.................... (0.07) (0.45) (0.26)
Distributions from net realized capital gains........... 0.00 (0.01) 0.00
------- ------- --------
Total distributions............................... (0.07) (0.46) (0.26)
------- ------- --------

Net asset value, end of period.......................... $ 10.17 $ 10.19 $ 10.23
======= ======= ========

Total return (%)........................................ 0.5*** 4.1 4.9***
Net assets, end of period (000)......................... $14,821 $13,460 $ 7,880
Ratio of operating expenses to average net assets (%)... 0.65** 0.65 0.65**
Ratio of net investment income to
average net assets (%)............................... 4.83** 4.58 5.30**
Portfolio turnover rate (%)............................. 7.8*** 17.5 18.4***
Without giving effect to the voluntary expense
limitation:
The ratio of operating expenses to
average net assets would have been (%)........... 1.15** 1.26 1.62**
The net investment income per share would have
been................................................ $ 0.14 $ 0.40 $ 0.22
</TABLE>

* Commencement of operations.
**Annualized.
***Not annualized.

5
<PAGE>

THE TRUST

The Fund is a series of the Trust. The Trust is a diversified open-end
management investment company which was organized as a Massachusetts business
trust on December 23, 1993. The Trust is authorized to issue an unlimited
number of full and fractional shares of beneficial interest in multiple series.
Shares are freely transferable and entitle shareholders to receive dividends as
determined by the Trust's board of trustees (the "Trustees") and to cast a vote
for each share held (with a fractional vote for each fractional share held) at
shareholder meetings. The Trust does not generally hold shareholder meetings
and will do so only when required by law. Shareholders may call meetings to
consider removal of the Trustees.

INVESTMENT OBJECTIVE AND POLICIES

The Fund's investment objective is to achieve as high a level of current
income exempt from both federal income tax and California personal income tax as
is consistent with preservation of capital.

The Fund seeks to attain its objective by normally investing substantially all
of its assets in securities the income from which is, in the opinion of the
issuer's counsel at the time of issuance, exempt from both federal income tax
and California personal income tax ("California tax exempt securities"). It is
a fundamental policy of the Fund that, during periods of normal market
conditions, at least 80% of its net assets will be invested in California tax
exempt securities. Normally at least 80% of its assets will be invested in
issues rated A or better by Standard & Poors ("S&P") or Moody's Investors
Service, Inc. ("Moody's"). All issues will be rated at least BBB by S&P or Baa
by Moody's (or, if unrated, be of equivalent credit quality as determined by
Loomis Sayles) at the time of purchase. Bonds of BBB or Baa quality have some
speculative characteristics. Changes in economic conditions or other
circumstances are more likely to lead to a weakened capacity of the issuers of
such bonds to make principal and interest payments than is the case with issuers
of higher grade bonds. In the event that the credit rating of a security held
by the Fund falls below investment grade (or, in the case of unrated securities,
Loomis Sayles determines that the quality of such security has deteriorated
below investment grade), the Fund will not be obligated to dispose of such
security and may continue to hold such security, if, in the opinion of Loomis
Sayles, such investment is appropriate in the circumstances.

The Fund may invest up to 20% of its net assets in high quality corporate
obligations, U.S. Government obligations and repurchase agreements. Income from
these investments may be subject to federal income tax and/or California
personal income tax.

The Fund will not "concentrate" its investments. That is, it will not invest
more than 25% of its total assets in any one industry. Although tax-exempt
securities secured by the assets or revenues of governmental entities are not
considered part of any "industry," for this purpose tax-exempt securities backed
only by the assets and revenues of nongovernmental entities are deemed to
represent investments in the industries of such nongovernmental issuers.

Notwithstanding the 25% industry limitation, it is possible that the Fund may
invest more than 25% of its assets in a broader segment of the market for tax-
exempt securities, such as revenue obligations of hospitals and other health
care facilities, housing revenue obligations, or airport revenue obligations.
This would be the case only if Loomis Sayles determined that the yields
available from obligations in a particular segment of the market justified the
additional risks associated with such concentration. Economic, business,
political and other developments may have a general adverse effect on all tax-
exempt securities in a particular market segment. (Examples would include
proposed legislation or pending court decisions affecting the financing of such
projects and market factors affecting the demand for their services or
products.)

Some of the Fund's investment restrictions are "fundamental" and cannot be
changed without a majority vote of the Fund's shareholders. Such restrictions
include: (1) a restriction prohibiting the Fund from making loans; (2) a
restriction prohibiting the Fund from purchasing a security if, as a result,
more than 25% of the Fund's total assets (taken at current value) would be
invested in any one industry; (3) a restriction prohibiting the Fund from
borrowing money in excess of 10% of its total assets (taken at cost) or 5% of
its total assets (taken at current value), whichever is lower, and from
borrowing any money except as a temporary measure for extraordinary or emergency
purposes; and (4) a restriction prohibiting the Fund from purchasing any
illiquid security including a security that is not readily marketable if, as a
result, more than 15% of the Fund's net assets based on current value would then
be invested in such securities. For additional investment restrictions, see the
Statement of Additional Information.

6
<PAGE>

offered securities that can be resold only to certain qualified institutional
buyers. Rule 144A securities are treated as illiquid, unless Loomis Sayles has
determined, under guidelines established by the Trustees, that the particular
issue of Rule 144A securities is liquid.

The investment objective of the Fund is "fundamental" and cannot be changed
without a majority vote of the Fund's shareholders. All investment policies
other than those identified as "fundamental" may be changed by the Trustees
without a vote of the Fund's shareholders.

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS

The net asset value of the Fund's shares will vary as a result of changes in
the value of securities in the Fund's portfolio. The following describes the
types of securities in which the Fund will principally invest and the risks
associated with them. Additional information about the Fund's investment
practices can be found in the Statement of Additional Information.

CALIFORNIA FISCAL CONDITION
- ---------------------------

Because the Fund will invest primarily in California tax exempt securities,
its performance may be especially affected by factors pertaining to the
California economy and other factors specifically affecting the ability of
issuers of California tax exempt securities to meet their obligations. As a
result, the value of the Fund's shares may fluctuate more widely than the value
of shares of a portfolio investing in securities relating to a number of
different states. The ability of state, county, or local governments to meet
their obligations will depend primarily on the availability of tax and other
revenues to those governments and on their fiscal conditions generally. An
expanded discussion of risks associated with California tax exempt securities is
contained in the Statement of Additional Information.

FIXED INCOME SECURITIES
- -----------------------

The Fund may invest in fixed income securities of any maturity. Fixed income
securities pay a specified rate of interest or dividends. The Fund may also
invest in other debt securities that pay a rate of interest or dividends that is
adjusted periodically by reference to some specified index or market rate. Such
securities are included within the definition of fixed income securities as used
in this Prospectus. Because interest rates vary, it is impossible to predict
the income of the Fund for any particular period.

Fixed income securities are subject to credit and market risk. Credit risk
relates to the ability of the issuer to make payments of principal and interest.
Market risk relates to changes in a security's value as a result of changes in
interest rates generally. In general, the values of fixed income securities
increase when prevailing interest rates fall and decrease when interest rates
rise. Generally, the longer the maturity of a fixed income security, the
greater the fluctuations in its value because of market and credit risk.

U.S. GOVERNMENT SECURITIES
- --------------------------

U.S. Government Securities have different kinds of government support. For
example, some U.S. Government Securities, such as U.S. Treasury bonds, are
supported by the full faith and credit of the United States, whereas certain
other U.S. Government Securities issued or guaranteed by federal agencies or
government-sponsored enterprises are not supported by the full faith and credit
of the United States.

Although U.S. Government Securities generally do not involve the credit risks
associated with other types of fixed income securities, the market values of
U.S. Government Securities will fluctuate as interest rates change. Thus, for
example, the value of an investment in U.S. Government Securities may fall
during times of rising interest rates. Yields on U.S. Government Securities
tend to be lower than those of other fixed income securities of comparable
maturities.

7
<PAGE>

at as favorable an interest rate. As a result of these principal prepayment
features, mortgage-backed securities are generally more volatile investments
than many other fixed income securities. In addition, slower than anticipated
prepayments on the underlying mortgages can extend the effective maturities of
mortgage-backed securities, subjecting them to a greater risk of decline in
market value in response to rising interest rates than traditional debt
securities.

In addition to investing directly in U.S. Government Securities, the Fund may
purchase certificates of accrual or similar instruments ("strips") evidencing
undivided ownership interests in interest payments or principal payments, or
both, in U.S. Treasury securities. These investment instruments may be highly
volatile.

COMMERCIAL MORTGAGE-BACKED SECURITIES
- -------------------------------------

The Fund may invest in commercial mortgage-backed securities. Commercial
mortgage-backed securities are securities that represent an interest in, or are
secured by, mortgage loans secured by commercial property, such as industrial
and warehouse properties, office buildings, retail space and shopping malls,
multifamily properties and cooperative apartments, hotels and motels, nursing
homes, hospitals, and senior living centers. The commercial mortgage-backed
securities market is newer and in terms of total outstanding principal amount of
issues is relatively small compared to the total size of the market for
residential mortgage-backed securities.

Commercial mortgage-backed securities are generally structured similarly to
pass-through securities or to collateralized mortgage obligations although other
structures are possible. They may pay fixed or adjustable rates of interest.
Commercial mortgage-backed securities have been issued in public or private
transactions by a variety of public and private issuers.

The commercial mortgage loans that underlie commercial mortgage-backed
securities have certain distinct risk characteristics. Commercial mortgage
loans generally lack standardized terms, which may complicate their structure.
Commercial properties themselves tend to be unique and are more difficult to
value than single-family residential properties. Commercial mortgage loans also
tend to have shorter maturities than residential mortgage loans, and may not be
fully amortizing, meaning that they have a significant principal balance, or
"balloon" payment, due on maturity. Assets underlying commercial mortgage-
backed securities may relate only to a few properties or a single property. The
risk involved in single property financings is highly concentrated. In
addition, commercial properties, particularly industrial and warehouse
properties, are subject to environmental risks and the burdens and costs of
compliance with environmental laws and regulations. At the same time,
commercial mortgage-backed securities may have a lower prepayment risk than
residential mortgage-backed securities, because commercial mortgage loans
generally prohibit or impose penalties on prepayments of principal. In
addition, commercial mortgage-backed securities often are structured with some
form of credit enhancement to protect against potential losses on the underlying
mortgage loans.

ZERO COUPON SECURITIES
- ----------------------

The Fund may invest in "zero coupon" fixed income securities. These
securities accrue interest at a specified rate, but do not pay interest in cash
on a current basis. The Fund is required to distribute the income on zero
coupon securities to Fund shareholders as the income accrues, even though the
Fund is not receiving the income in cash on a current basis. Thus the Fund may
be forced to sell other investments to obtain cash to make income distributions
at times when Loomis Sayles would not otherwise deem it advisable to do so. The
market value of zero coupon securities is generally more volatile than that of
non-zero coupon fixed income securities of comparable quality and maturity.

WHEN-ISSUED SECURITIES
- ----------------------

The Fund may purchase securities on a "when-issued" basis. This means that
the Fund will enter into a commitment to buy the security before the security
has been issued. The Fund's payment obligation and the interest rate on the
security are determined when the Fund enters into the commitment. The security
is typically delivered to the Fund 15 to 120 days later. No interest accrues on
the security between the time the Fund enters into the commitment and the time
the security is issued. If the value of the security being purchased falls
between the time the Fund commits to buy it and the payment date, the Fund may
sustain a loss. The risk of this loss is in addition to the Fund's risk of loss
on the securities actually in its portfolio at the time. When the Fund buys a
security on a when-issued basis, it is subject to the risk that market rates of
interest will increase before the time the security is delivered, with the
result that the yield on the security delivered to the Fund may be lower than
the yield available on other, comparable securities at time of delivery. If the
Fund has outstanding

8
<PAGE>

obligations to buy when-issued securities, it will maintain liquid assets in a
segregated account at its custodian bank in an amount sufficient to satisfy
these obligations.

REPURCHASE AGREEMENTS
- ---------------------

The Fund may enter into repurchase agreements, by which the Fund purchases a
security and obtains a simultaneous commitment from the seller (a bank or, to
the extent permitted by the Investment Company Act of 1940, as amended, a
recognized securities dealer) to repurchase the security at an agreed upon price
and date (usually seven days or less from the date of original purchase). The
resale price is in excess of the purchase price and reflects an agreed upon
market rate unrelated to the coupon rate on the purchased security. Such
transactions afford the Fund the opportunity to earn a return on temporarily
available cash. Although the underlying security may be a bill, certificate of
indebtedness, note or bond issued by an agency, authority or instrumentality of
the U.S. Government, the obligation of the seller is not guaranteed by the U.S.
Government and there is a risk that the seller may fail to repurchase the
underlying security. In such event, the Fund would attempt to exercise rights
with respect to the underlying security, including possible disposition in the
market. However, the Fund may be subject to various delays and risks of loss,
including (a) possible declines in the value of the underlying security during
the period while the Fund seeks to enforce its rights thereto and (b) inability
to enforce rights and the expenses involved in attempted enforcement.

YEAR 2000
- ---------

Many computer software systems in use today cannot properly process date-
related information from and after January 1, 2000. Should any of the computer
systems employed by the Fund's major service providers fail to process this type
of information properly, that could have a negative impact on the Fund's
operations and the services that are provided to the Fund's shareholders.
Loomis Sayles has advised the Fund that it is reviewing all of its computer
systems with the goal of modifying or replacing such systems prior to January 1,
2000, to the extent necessary to foreclose any such negative impact. In
addition, Loomis Sayles has been advised by the Fund's custodian that it is also
in the process of reviewing its systems with the same goal. As of the date of
this prospectus, the Fund and Loomis Sayles have no reason to believe that these
goals will not be achieved. Similarly, the values of certain of the portfolio
-------------------------------------------------
securities held by the Fund may be adversely affected by the inability of the
- -----------------------------------------------------------------------------
securities' issuers or of third parties to process this type of information
- ---------------------------------------------------------------------------
properly.
- ---------

THE FUND'S INVESTMENT ADVISER

The Fund's investment adviser is Loomis Sayles, One Financial Center, Boston,
Massachusetts 02111. Founded in 1926, Loomis Sayles is one of the country's
oldest and largest investment firms. The general partner of Loomis Sayles is a
special purpose corporation that is an indirect wholly-owned subsidiary of Nvest
Companies, L.P. ("Nvest Companies"). Nvest Companies' managing general partner,
Nvest Corporation, is a direct wholly-owned subsidiary of Metropolitan Life
Insurance Company ("Met Life"), a mutual life insurance company. Nvest
Companies' advising general partner, Nvest, L.P., is a publicly traded company
listed on the New York Stock Exchange. Nvest Corporation is the sole general
partner of Nvest L.P.

In addition to selecting and reviewing the Fund's investments, Loomis Sayles
provides executive and other personnel for the management of the Fund. The
Board of Trustees supervises Loomis Sayles's conduct of the affairs of the Fund.

The portfolio managers for the Fund since its inception have been Kent P.
Newmark and Robert K. Payne. Mr. Newmark is a Vice President of Loomis Sayles
and a Managing Partner of its San Francisco office. Mr. Payne is a Vice
President of Loomis Sayles. Mr. Newmark has been with Loomis Sayles since 1976
and Mr. Payne has been with Loomis Sayles since 1982.

9
<PAGE>

FUND EXPENSES

The Fund pays Loomis Sayles a monthly investment advisory fee. This fee is
paid at the annual rate of 0.50% of the Fund's average daily net assets.

In addition to the investment advisory fee, the Fund pays all expenses not
expressly assumed by Loomis Sayles, including taxes, brokerage commissions, fees
of the Fund's custodian, independent accountants and legal counsel and fees of
the Trustees who are not directors, officers or employees of Loomis Sayles or
its affiliated companies.

Loomis Sayles has voluntarily undertaken for an indefinite period to waive its
fees and, to the extent necessary, to bear other Fund expenses in order to limit
the Fund's total operating expenses to .65% of average annual net assets.

PORTFOLIO TRANSACTIONS

Loomis Sayles selects brokers and dealers to execute portfolio transactions
for the Fund. Portfolio turnover considerations will not limit Loomis Sayles's
investment discretion in managing the Fund's assets. The Fund anticipates that
its portfolio turnover rates will vary significantly from time to time depending
on the volatility of economic and market conditions. High portfolio turnover
may result in higher costs such as higher brokerage commissions and higher
levels of taxable gains. Portfolio turnover rates for the life of the Fund are
set forth above under the headings "Financial Highlights" and "Prior
Performance." See "Dividends, Capital Gain Distributions and Taxes" for
information on the tax consequences of investing in the Fund.

HOW TO PURCHASE SHARES

You may make an initial purchase of shares of the Fund by submitting a
completed application form and payment to Loomis Sayles. The minimum initial
investment in the Fund is $500,000. Subsequent investments must be at least
$50,000. The Trust reserves the right to waive these minimums in its sole
discretion.

Shares of the Fund may be purchased by exchange of (i) cash, (ii) securities
on deposit with a custodian acceptable to Loomis Sayles or (iii) a combination
of such securities and cash. Purchase of shares of the Fund in exchange for
securities is subject in each case to the determination by Loomis Sayles that
the securities to be exchanged are acceptable for purchase by the Fund.
Securities accepted by Loomis Sayles in exchange for Fund shares will be valued
in the same manner as the Fund's assets, as described below, as of the time of
the Fund's next determination of net asset value after such acceptance. All
dividends and subscription or other rights which are reflected in the market
price of accepted securities at the time of valuation become the property of the
Fund and must be delivered to the Fund upon receipt by the investor from the
issuer. A gain or loss for federal income tax purposes would be realized upon
the exchange of any securities tendered. A shareholder who wishes to purchase
shares by exchanging securities should obtain instructions by calling (617) 482-
2450.

Loomis Sayles will not approve the acceptance of securities in exchange for
shares of the Fund unless (1) Loomis Sayles, in its sole discretion, believes
the securities are appropriate investments for the Fund; (2) the investor
represents and agrees that all securities offered to the Fund can be resold by
the Fund without restriction under the 1933 Act or otherwise; and (3) the
securities are eligible to be acquired under the Fund's investment policies and
restrictions. No investor owning 5% or more of the Fund's shares may purchase
additional Fund shares by the exchange of securities.

Upon acceptance of your order, the Trust opens an account for you, applies the
payment to the purchase of full and fractional Fund shares and mails a statement
of the account confirming the transaction. After an account has been
established, you may send subsequent investments at any time.

The Trust reserves the right to reject any purchase order for any reason which
the Trust in its sole discretion deems appropriate. Although the Trust does not
anticipate that it will do so, the Trust reserves the right to suspend or change
the terms of the offering of its shares.

The price you pay will be the per share net asset value next calculated after
a proper investment order is received by the Trust. Shares of the Fund are sold
without any sales charge. The net asset value of the Fund's shares is
calculated by dividing the Fund's net assets by the number of shares
outstanding. Net asset value is calculated at least weekly and as of the close
of the New York Stock Exchange (the "Exchange") on each day on which an order
for purchase or redemption of Fund shares is received and on which the Exchange
is open for unrestricted trading. Portfolio securities are valued at their
market value as more fully described in the Statement of Additional Information.

10
<PAGE>

HOW TO REDEEM SHARES

You can redeem your shares by sending a written request to the Trust.

The written request must include the name of the Fund, your account number,
the exact name(s) in which your shares are registered, and the number of shares
or the dollar amount to be redeemed. All owners of the shares must sign the
written request in the exact names in which the shares are registered and should
indicate any special capacity in which they are signing (such as trustee or
custodian or on behalf of a partnership, corporation or other entity).

The redemption price will be the net asset value per share next determined
after the written redemption request is received by the Trust in proper form.
The Trust usually requires additional documentation for the sale of shares by a
corporation, partnership, agent or fiduciary, or a surviving joint owner.
Contact the Trust by calling (617) 482-2450 for details.

Proceeds resulting from a written redemption request will normally be mailed
to you within seven days after receipt of your request in good order. If you
purchased your shares by check and your check was deposited less than fifteen
days prior to the redemption request, the Trust may withhold redemption proceeds
until your check has cleared.

Redemption proceeds may be made in money or in kind, or partly in money and
partly in kind, as determined by the Trust.

The Fund may suspend the right of redemption and may postpone payment for more
than seven days when the Exchange is closed for other than weekends or holidays,
or if permitted by the rules of the SEC when trading on the Exchange is
restricted or during an emergency which makes it impracticable for the Fund to
dispose of its securities or to determine fairly the value of its net assets, or
during any other period permitted by the SEC for the protection of investors.

OTHER INFORMATION

The Trustees may, without shareholder approval, divide the Trust's shares of
beneficial interest into multiple series. The Trust is currently divided into
seven series, including the Fund and the other funds listed on the cover of this
Prospectus.

The Fund's investment performance may from time to time be included in
advertisements about the Fund.

The Fund's yield will be computed by dividing the Fund's net investment income
for a recent 30-day period by the maximum offering price (reduced by any
undeclared earned income expected to be paid shortly as a dividend) on the last
trading day of that period.

Total return for the Fund is measured by comparing the value of an investment
in the Fund at the beginning of the relevant period to the redemption value of
the investment in the Fund at the end of the period (assuming immediate
reinvestment of any dividends or capital gain distributions).

All data are based on the Fund's past investment results and do not predict
future performance. Investment performance, which will vary, is based on many
factors, including market conditions, the composition of the Fund's portfolio
and the Fund's operating expenses. Investment performance also often reflects
the risks associated with the Fund's investment objectives and policies. These
factors should be considered when comparing the Fund's investment results with
those of other mutual funds and other investment vehicles. Quotations of
investment performance for any period when an expense limitation was in effect
will be greater than if the limitation had not been in effect.

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES

The Fund pays its net investment income to shareholders as dividends monthly.
Any capital gain distributions are normally made annually in December, but may,
to the extent permitted by law, be made more frequently as deemed advisable by
the Trustees. The Fund distributes annually in December all of its net capital
gains realized from the sale of portfolio securities. The Trustees may change
the frequency with which the Fund declares or pays dividends.

11
<PAGE>

Your dividends and capital gain distributions will automatically be reinvested
in additional shares of the Fund on the payment date unless you have elected to
receive cash.

The Fund intends to qualify as a "regulated investment company" under the
Internal Revenue Code of 1986, as amended. As such, so long as the Fund
distributes substantially all its net investment income and net capital gains to
its shareholders, the Fund itself does not pay any federal income or excise tax.

Fund dividends designated as "exempt-interest dividends" are not generally
subject to federal income tax or California personal income tax (to the extent
derived from California tax exempt securities). However, an investment in the
Fund may result in liability for federal alternative minimum tax for corporate
and individual shareholders, and in California franchise or corporation income
tax for corporate shareholders subject to such tax. Of the dividends paid by
the Fund from net investment income for the fiscal year ended December 31, 1997,
92% of such dividends constituted exempt-interest dividends for regular federal
income tax purposes.

It is anticipated that the Fund will be operated so that its dividends will be
exempt-interest dividends. However, as described under "Investment Objective
and Policies," certain investments of the Fund may produce taxable income.
Distributions of such income will be taxable to you as ordinary income, except
that any distributions designated by the Fund as deriving from net gains on
securities held for more than one year but not more than 18 months or from net
gains on securities held for more than 18 months will be taxable to you as such,
regardless of how long you have owned shares of the Fund. These distributions
will be taxable as described whether distributed in cash or additional shares.

The Fund may at times purchase California tax exempt securities at a discount
from the price at which they were originally issued. For federal income tax
purposes and California personal income tax purposes, some or all of this market
discount will be included in the Fund's ordinary income and will be taxable to
you as such when it is distributed to you.

If you incur or continue indebtedness to purchase or carry shares of the Fund,
that portion of interest paid or accrued on such indebtedness that equals the
total interest paid or accrued on the indebtedness, multiplied by the percentage
of the Fund's total distributions (not including distributions from net long-
term capital gains) paid to you that are exempt-interest dividends, is not
deductible for federal income tax purposes. The Internal Revenue Service may
consider the purchase of shares to have been made with borrowed funds even
though such funds are not directly traceable to the purchase of shares.

Under the Code, if you sell a share of the Fund after holding it for six
months or less, any loss on the sale or exchange of such share will be
disallowed to the extent of the amount of any exempt-interest dividends that you
have received with respect to the share that is sold and will be treated as a
long-term capital loss to the extent of any long-term capital gain distributions
received with respect to such share.

If you receive social security or railroad retirement benefits, you may be
taxed at the federal level on a portion of those benefits as a result of
receiving tax-exempt income (including exempt-interest dividends distributed by
the Fund). California personal income tax does not apply to social security or
railroad retirement benefits.

The Fund is required to withhold 31% of any redemption proceeds and all
taxable income dividends and capital gain distributions it pays to you (1) if
you do not provide a correct, certified taxpayer identification number, (2) if
the Fund is notified that you have under reported income in the past, or (3) if
you fail to certify to the Fund that you are not subject to such
withholding.

In January of each year, the Trust will send you a statement showing the tax
status of dividends and distributions paid to you during the preceding
year.

The foregoing summarizes certain tax consequences of investing in the Fund.
Before investing, you should consult your own tax adviser for more information
concerning the federal, foreign, state and local tax consequences of investing
in, redeeming or exchanging Fund shares.

TRANSFER AND DIVIDEND INVESTMENT ADVISER
PAYING AGENT AND Loomis, Sayles & Company, L.P.
CUSTODIAN OF ASSETS One Financial Center

12
<PAGE>

State Street Bank and Trust Company Boston, Massachusetts 02111
Boston, Massachusetts 02102

13
<PAGE>

APPENDIX A

DESCRIPTION OF BOND RATINGS ASSIGNED BY
STANDARD & POOR'S AND
MOODY'S INVESTORS SERVICE, INC.

STANDARD & POOR'S
- -----------------

AAA

This is the highest rating assigned by Standard & Poor's to a debt obligation
and indicates an extremely strong capacity to pay interest and repay principal.

Bonds rated AA also qualify as high quality debt obligations. Capacity to pay
interest and repay principal is very strong, and in the majority of instances
they differ from AAA issues only in small degree.

Bonds rated A have a strong capacity to pay interest and repay principal,
although they are somewhat more susceptible to the adverse effects of changes in
circumstances and economic conditions than obligations in higher rated
categories.

BBB

Bonds rated BBB are regarded as having an adequate capacity to pay interest and
repay principal. Whereas they normally exhibit adequate protection parameters,
adverse economic conditions or changing circumstances are more likely to lead to
a weakened capacity to repay principal and pay interest for bonds in this
category than for bonds in higher rated categories.

BB, B, CCC, CC

Bonds rated BB, B, CCC and CC are regarded, on balance, as predominantly
speculative with respect to capacity to pay interest and repay principal in
accordance with the terms of the obligation. BB indicates the lowest degree of
speculation and CC the highest degree of speculation. While such bonds will
likely have some quality and protective characteristics, these are outweighed by
large uncertainties or major risk exposures to adverse conditions.

The rating C is reserved for income bonds on which no interest is being paid.

Bonds rated D are in default, and payment of interest and/or repayment of
principal is in arrears.

This symbol is attached to the ratings of instruments with significant noncredit
risks such as risks to principal or volatility of expected returns.

Plus (+) or Minus (-): The ratings from "AA" to "B" may be modified by the
addition of a plus or minus sign to show relative standing within the major
rating categories.

A-1
<PAGE>

MOODY'S INVESTORS SERVICE, INC.
- -------------------------------

AAA

Bonds that are rated Aaa are judged to be of the best quality. They carry the
smallest degree of investment risk and are generally referred to as "gilt
edged." Interest payments are protected by a large, or by an exceptionally
stable, margin, and principal is secure. While the various protective elements
are likely to change, such changes as can be visualized are most unlikely to
impair the fundamentally strong position of such issues.

Bonds that are rated Aa are judged to be high quality by all standards.
Together with the Aaa group they comprise what are generally known as high grade
bonds. They are rated lower than the best bonds because margins of protection
may not be as large as in Aaa securities or fluctuation of protective elements
may be of greater amplitude or there are other elements present that make the
long-term risks appear somewhat larger than in Aaa securities.

Bonds that are rated A possess many favorable investment attributes and are to
be considered as upper medium grade obligations. Factors giving security to
principal and interest are considered adequate, but elements may be present that
suggest a susceptibility to impairment sometime in the future.

BAA

Bonds that are rated Baa are considered as medium grade obligations; i.e., they
are neither highly protected nor poorly secured. Interest payments and
principal security appear adequate for the present, but certain protective
elements may be lacking or may be characteristically unreliable over any great
length of time. Such bonds lack outstanding investment characteristics and, in
fact, have speculative characteristics as well.

Bonds which are rated Ba are judged to have speculative elements; their future
cannot be considered as well assured. Often, the protection of interest and
principal payments may be very moderate, and thereby not well safeguarded during
both good and bad times over the future. Uncertainty of position characterizes
bonds in this class.

Bonds which are rated B generally lack characteristics of the desirable
investment. Assurance of interest and principal payments or of maintenance of
other terms of the contract over any long period of time may be small.

CAA

Bonds which are rated Caa are of poor standing. Such issues may be in default
or there may be present elements of danger with respect to principal or
interest.

Bonds which are rated Ca represent obligations which are speculative in a high
degree. Such issues are often in default or have other marked shortcomings.

Bonds which are rated C are the lowest rated class of bonds, and issues so rated
can be regarded as having extremely poor prospects of ever attaining any real
investment standing.

15
<PAGE>

Should no rating be assigned by Moody's, the reason may be one of the following:

1. An application for rating was not received or accepted.

2. The issue or issuer belongs to a group of securities that are not
rated as a matter of policy.

3. There is lack of essential data pertaining to the issue or issuer.

4. The issue was privately placed in which case the rating is not
published in Moody's publications.

Suspension or withdrawal may occur if new and material circumstances arise, the
effects of which preclude satisfactory analysis; if there is no longer available
reasonable up-to-date data to permit a judgment to be formed; if a bond is
called for redemption; or for other reasons.

Note: Those bonds in the Aa, A, Baa, Ba and B groups which Moody's believes
possess the strongest investment attributes are designated by the symbols Aa1,
A1, Baa1, Ba1 and B1, and those with the weakest investment attributes are
designated by the symbols Aa3, A3, Baa3, Ba3 and B3.

16
<PAGE>

LOOMIS SAYLES INVESTMENT TRUST

LOOMIS SAYLES CORE FIXED INCOME FUND

ONE FINANCIAL CENTER
BOSTON, MASSACHUSETTS 02111
(617) 482-2450

PROSPECTUS

APRIL 22, 1998

The Loomis Sayles Investment Trust (the "Trust") is a group of seven mutual
funds including the Loomis Sayles Core Fixed Income Fund (the "Fund"). The
other series, which are described in separate prospectuses, are:

Loomis Sayles California Tax-Free Income Fund
Loomis Sayles Core Growth Fund
Loomis Sayles Fixed Income Fund
Loomis Sayles High Yield Fixed Income Fund
Loomis Sayles Intermediate Duration Fixed Income Fund
Loomis Sayles Investment Grade Fixed Income Fund

Except for the California Tax-Free Income Fund, the funds are designed
specifically for tax-exempt investors such as pension plans, endowments and
foundations, although other institutions and high net-worth individuals are
eligible to invest. Each of the funds is separately managed and has its own
investment objective and policies. Loomis, Sayles & Company, L.P. ("Loomis
Sayles") is the investment adviser of each of the funds.

TABLE OF CONTENTS

<TABLE>
<S> <C>
SUMMARY OF EXPENSES.............................................. -3-

FINANCIAL HIGHLIGHTS............................................. -4-

PRIOR PERFORMANCE................................................ -5-

THE TRUST........................................................ -6-

INVESTMENT OBJECTIVE AND POLICIES................................ -6-

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS.................... -7-

THE FUND'S INVESTMENT ADVISER....................................-10-

FUND EXPENSES....................................................-10-

PORTFOLIO TRANSACTIONS...........................................-11-

HOW TO PURCHASE SHARES...........................................-11-

HOW TO REDEEM SHARES.............................................-11-

OTHER INFORMATION................................................-12-

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES..................-12-

APPENDIX A A-1
</TABLE>

2
<PAGE>

SUMMARY OF EXPENSES

The following information is provided to assist you in understanding the
various costs and expenses that, as an investor in the Fund, you will bear
directly or indirectly. The information is based on annualized expenses for the
Fund's fiscal year ended December 31, 1997. The information below should not be
considered a representation of past or future expenses, as actual expenses may
be greater or less than those shown. Also, the assumed 5% annual return in the
example should not be considered a representation of investment performance, as
actual performance will depend upon the actual investment results of securities
held in the Fund's portfolio.

<TABLE>
<S> <C>
Shareholder Transaction Expenses:
Maximum Sales Load Imposed on
Purchases (as a percentage of offering price) none
Maximum Sales Load Imposed on
Reinvested Dividends (as a percentage of
offering price) none
Deferred Sales Load (as a
percentage of original
purchase price or redemption
proceeds as applicable) none
Redemption Fees (as a percentage
of amount redeemed) none
Exchange Fees none

Annual Fund Operating Expenses
(as a percentage of average net assets)
Management Fees: .50%
12b-1 Fees none
Other Operating Expenses (after expense
limitation)/1/: .15%
Total Fund Operating Expenses (after
expense limitation)/1/: .65%

Example
You would pay the following
expenses on a $1,000 investment
assuming a 5% annual return
(with or without a redemption at
the end of each time period):

One Year $ 7
Three Years $21
Five Years $36
Ten Years $81
</TABLE>

______________________________

/1/ Loomis Sayles has voluntarily undertaken for an indefinite period to limit
the Fund's total Fund operating expenses to the percentage of average net assets
shown above. In the absence of the voluntary expense limitation. Other
Operating Expenses and Total Fund Operating Expenses for the fiscal year ended
December 31, 1997 would have been 1.30% and 1.80%, respectively.

3
<PAGE>

FINANCIAL HIGHLIGHTS

<TABLE>
<CAPTION>
March 7+ through
December 31, 1997
------------------
<S> <C>
Net asset value, beginning of period......................... $ 10.15

Income from investment operations -
Net investment income....................................... 0.27
Net realized and unrealized gain (loss) on investments...... 0.66
-------
Total from investment operations.......................... 0.93

Less distributions -
Dividends from net investment income........................ (0.39)
Distributions from net realized capital gains............... (0.03)
-------
Total distributions....................................... (0.42)
-------
Net asset value, end of period............................... $ 10.66
=======

Total return (%)............................................. 9.1**
Net assets, end of period (000).............................. $16,110
Ratio of operating expenses to average net assets (%)........ 0.65*
Ratio of net investment income to average net assets (%)..... 6.30*
Portfolio turnover rate (%).................................. 34.1**
Without giving effect to the voluntary expense limitations:
The ratio of operating expenses to average net assets
would have been (%)........................................ 1.76*
The net investment income per share would have been......... $ 0.22
</TABLE>

+Date of effectiveness of the Fund's registration statement under the Securities
Act of 1933, as amended.
*Annualized.
**Not annualized.

4
<PAGE>

PRIOR PERFORMANCE

(FOR A SHARE OF THE FUND OUTSTANDING THROUGHOUT THE INDICATED PERIODS)

The information presented below, for the periods indicated, relates to
periods prior to the effectiveness of the Fund's registration statement under
the Securities Act of 1933, as amended (the "1933 Act"). The following
information should be read in conjunction with the financial highlights,
financial statements, and notes thereto that have been audited by Coopers &
Lybrand, L.L.P., independent accountants, whose report thereon appears in the
Fund's 1997 Annual Report, which is incorporated by reference into this
Prospectus and the Statement of Additional Information. The Fund is managed in a
manner that is in all material respects similar to the manner in which it was
managed prior to the effectiveness of its registration statement under the 1933
Act.

<TABLE>
<CAPTION>
January 1, 1997 April 24* through
through March 6, 1997 December 31, 1996
---------------------- ------------------
<S> <C> <C>
Net asset value, beginning of period......................... $ 10.14 $ 10.00
Income from investment operations -
Net investment income..................................... 0.12 0.40
Net realized and unrealized gain (loss) on investments.... (0.11) 0.13
-------- --------
Total from investment operations......................... 0.01 0.53

Less dividends from net investment income.................... 0.00 (0.39)
-------- --------

Net asset value, end of period............................... $ 10.15 $ 10.14
======== ========

Total return (%)............................................. 0.1*** 5.3***
Net assets, end of period (000).............................. $ 6,280 $ 6,271
Ratio of operating expenses to average net assets (%)........ 0.65** 0.65**
Ratio of net investment income to average net assets (%)..... 6.62** 6.21**
Portfolio turnover rate (%).................................. 33.4*** 33.8***
Without giving effect to the voluntary expense limitations:
The ratio of operating expenses to average net assets
would have been (%)........................................ 2.12** 1.46**
The net investment income per share would have been......... $ 0.09 $ 0.35
</TABLE>

* Commencement of operations.
**Annualized.
***Not annualized.

5
<PAGE>

THE TRUST

The Fund is a series of the Trust. The Trust is a diversified open-end
management investment company which was organized as a Massachusetts business
trust on December 23, 1993. The Trust is authorized to issue an unlimited number
of full and fractional shares of beneficial interest in multiple series. Shares
are freely transferable and entitle shareholders to receive dividends as
determined by the Trust's board of trustees (the "Trustees") and to cast a vote
for each share held (with a fractional vote for each fractional share held) at
shareholder meetings. The Trust does not generally hold shareholder meetings and
will do so only when required by law. Shareholders may call meetings to consider
removal of the Trustees.

INVESTMENT OBJECTIVE AND POLICIES

The Fund's investment objective is high total return through a combination
of current income and capital appreciation.

The Fund seeks to attain its objective by investing primarily in fixed
income securities issued or guaranteed by the U.S. Government or its agencies,
certain types of mortgage-related and asset-backed securities (including
interest-only and principal-only ("IOs" and "POs") classes of mortgage-backed
securities), and investment grade corporate and sovereign debt obligations.
Under normal market conditions, the Fund will invest at least 65% of its total
assets in fixed income securities. All securities will be denominated in U.S.
dollars.

U.S. Government Securities include obligations issued or guaranteed by the
U.S. Government or its authorities, agencies or instrumentalities and
certificates representing undivided interests in the interest or principal of
U.S. Treasury Securities. U.S. Government Securities will be held for the
purpose of maintaining high average portfolio quality, providing sufficient
liquidity and controlling interest rate exposure.

The Fund normally will maintain a significant portion of its assets in
investment grade corporate bonds and mortgage-related securities in order to
provide a high level of current income. In order to attain capital appreciation,
the Fund seeks to identify and select those corporate and sovereign debt
obligations undergoing credit improvement which is likely to result in a credit
rating upgrade. The Fund may invest in corporate and sovereign debt securities
that are rated at least investment grade by both Standard & Poor's (BBB-) and
Moody's Investor Service, Inc. (Baa3), or if unrated, determined to be of
comparable quality by Loomis Sayles. In the event, however, that the credit
rating of a security held by the Fund falls below investment grade (or, in the
case of unrated securities, Loomis Sayles determines that the quality of such
security has deteriorated below investment grade), the Fund will not be
obligated to dispose of such security and may continue to hold such security, if
in the opinion of Loomis Sayles, such investment is considered appropriate in
the circumstances. Collateralized mortgage obligations ("CMOs") will be limited
to those with CMO market risk ratings of V-1 to V-4 from Fitch Investors
Service, L.P. ("Fitch"), or CMOs unrated by Fitch that are determined by Loomis
Sayles to be of comparable volatility.

Some of the Fund's investment restrictions are "fundamental" and cannot be
changed without a majority vote of the Fund's shareholders. Such restrictions
include: (1) a restriction prohibiting the Fund from making loans; (2) a
restriction prohibiting the Fund from purchasing a security (other than U.S.
Government Securities) if, as a result, more than 25% of the Fund's total assets
(taken at current value) would be invested in any one industry; (3) a
restriction prohibiting the Fund from borrowing money in excess of 10% of its
total assets (taken at cost) or 5% of its total assets (taken at current value),
whichever is lower, and from borrowing any money except as a temporary measure
for extraordinary or emergency purposes; and (4) a restriction prohibiting the
Fund from purchasing any illiquid security including a security that is not
readily marketable if, as a result, more than 15% of the Fund's net assets based
on current value would then be invested in such security. For additional
investment restrictions, see the Statement of Additional Information.

6
<PAGE>

illiquid, unless Loomis Sayles has determined, under guidelines established by
the Trustees, that the particular issue of Rule 144A securities is liquid.

The investment objective of the Fund is "fundamental" and cannot be changed
without a majority vote of the Fund's shareholders. All investment policies
other than those that are identified as "fundamental" may be changed by the
Trustees without a vote of the Fund's shareholders.

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS

The net asset value of the Fund's shares will vary as a result of changes
in the value of securities in the Fund's portfolio. The following describes the
types of securities in which the Fund will principally invest and the risks
associated with them. Additional information about the Fund's investment
practices can be found in the Statement of Additional Information.

FIXED INCOME SECURITIES
- -----------------------

The Fund may invest in fixed income securities of any maturity. Fixed
income securities pay a specified rate of interest or dividends. Fixed income
securities include securities issued by federal, state, local and foreign
governments and related agencies, and by a wide range of foreign and domestic
private issuers. The Fund may also invest in other debt securities that pay a
rate of interest or dividends that is adjusted periodically by reference to some
specified index or market rate. Such securities are included within the
definition of fixed income securities as used in this Prospectus other than for
purposes of determining compliance with the Fund's investment policy of
investing, under normal market conditions, at least 65% of its total assets in
fixed income securities. Because interest rates vary, it is impossible to
predict the income of the Fund for any particular period.

Fixed income securities are subject to market and credit risk. Market risk
relates to changes in a security's value as a result of changes in interest
rates generally. In general, the values of fixed income securities increase when
prevailing interest rates fall and decrease when interest rates rise. Credit
risk relates to the ability of the issuer to make payments of principal and
interest. Generally, the longer the maturity of a fixed income security, the
greater the fluctuations in its value because of market and credit risk.

U.S. GOVERNMENT SECURITIES
- --------------------------

Although U.S. Government Securities generally do not involve the credit
risks associated with other types of fixed income securities, the market values
of U.S. Government Securities will fluctuate as interest rates change. Thus, for
example, the value of an investment in U.S. Government Securities may fall
during times of rising interest rates. Yields on U.S. Government Securities tend
to be lower than those of other fixed income securities of comparable
maturities.

Some U.S. Government Securities, such as Government National Mortgage
Association Certificates, are known as "mortgage-backed" securities representing
interests in "pools" of mortgage loans secured by residential or commercial real
property. Interest and principal payments on the mortgages underlying mortgage-
backed U.S. Government Securities are passed through to the holders of the
security. If the Fund purchases mortgage-backed securities at a discount or a
premium, the Fund will recognize a gain or loss when the payments of principal,
through prepayment or otherwise, are passed through to the Fund and, if the
payment occurs in a period of falling interest rates, the Fund may not be able
to reinvest the payment at as favorable an interest rate. As a result of these
principal prepayment features, mortgage-backed securities are generally more
volatile investments than many other fixed income securities. See
"Collateralized Mortgage Obligations" below for additional information regarding
the risks associated with mortgage-backed securities.

7
<PAGE>

In addition to investing directly in U.S. Government Securities, the Fund
may purchase certificates of accrual or similar instruments ("strips")
evidencing undivided ownership interests in interest payments or principal
payments, or both, in U.S. Treasury securities. These investment instruments may
be highly volatile.

ZERO COUPON SECURITIES
- ----------------------

The Fund may invest in "zero coupon" fixed income securities. These
securities accrue interest at a specified rate, but do not pay interest in cash
on a current basis. The Fund is required to distribute the income on zero coupon
securities to Fund shareholders as the income accrues, even though the Fund is
not receiving the income in cash on a current basis. Thus the Fund may be forced
to sell other investments to obtain cash to make income distributions at times
when Loomis Sayles would not otherwise deem it advisable to do so. The market
value of zero coupon securities is generally more volatile than that of non-zero
coupon fixed income securities of comparable quality and maturity.

COLLATERALIZED MORTGAGE OBLIGATIONS
- -----------------------------------

The Fund may invest in collateralized mortgage obligations ("CMOs"). A CMO
is a limited recourse security backed by a portfolio of mortgages or, more
typically, by mortgage-backed securities held under an indenture. CMOs may be
issued by instrumentalities of the U.S. Government or by non-governmental
entities. The issuer's obligation to make interest and principal payments is
derived from and secured by the underlying portfolio of mortgages or mortgage-
backed securities. CMOs are issued with a number of classes or series which have
different maturities and which may represent interests in some or all of the
interest or principal payments on the underlying collateral or a combination
thereof. CMOs of different classes or series are generally retired in sequence
as the underlying mortgage loans in the mortgage pool are repaid. In the event
of sufficient early prepayments on such mortgages, the class or series of CMOs
first to mature generally will be retired prior to its maturity. A faster than
anticipated rate of prepayments will generally result in losses on CMOs
representing interests in the interest payments on the underlying portfolio of
mortgage-backed securities. As with other mortgage-backed securities, the early
retirement of a particular class or series of CMOs held by the Fund could
involve the loss of any premium the Fund paid when it acquired the investment
and could result in the Fund's reinvesting the proceeds at a lower interest rate
than the interest rate paid by the retired CMO. Because of the early retirement
feature, CMOs may be more volatile than many other fixed income investments. In
addition, slower than anticipated prepayments on the underlying mortgages can
extend the effective maturities of CMOs, subjecting them to a greater risk of
decline in market value in response to rising interest rates than traditional
debt securities. The Fund will invest only in CMOs with Fitch ratings of V-4 or
better, or in CMOs unrated by Fitch that are determined by Loomis Sayles to be
of comparable volatility. Even CMOs with ratings reflecting the lowest market
risk are likely to experience losses in the event of adverse changes in market
conditions.

COMMERCIAL MORTGAGE-BACKED SECURITIES
- -------------------------------------

Commercial mortgage-backed securities are generally structured similarly to
pass-through securities or to CMOs, although other structures are possible. They
may pay fixed or adjustable rates of interest. Commercial mortgage-backed
securities have been issued in public or private transactions by a variety of
public and private issuers.

8
<PAGE>

involved in single property financings is highly concentrated. In addition,
commercial properties, particularly industrial and warehouse properties, are
subject to environmental risks and the burdens and costs of compliance with
environmental laws and regulations.

STRIPPED MORTGAGE-BACKED SECURITIES
- -----------------------------------

The Fund may invest in interest-only and principal-only ("IOs" and "POs")
classes of mortgage-backed securities. The yield to maturity on an IO or PO
class of stripped mortgage-backed securities is extremely sensitive not only to
changes in prevailing interest rates but also to the rate of principal payments
(including prepayments) on the underlying assets. A rapid rate of principal
prepayments may have a measurably adverse effect on the fund's yield to maturity
to the extent it invests in IOs. If the assets underlying the IOs experience
greater than anticipated prepayments of principal, the fund may fail to recoup
fully its initial investment in these securities. Conversely, POs tend to
increase in value if prepayments are greater than anticipated and decline if
prepayments are slower than anticipated.

In either event, the secondary market for stripped mortgage-backed
securities may be more volatile and less liquid than that for other mortgage-
backed securities, potentially limiting the fund's ability to buy or sell those
securities at any particular time.

WHEN-ISSUED SECURITIES
- ----------------------

The Fund may purchase securities on a "when-issued" basis. This means that
the Fund will enter into a commitment to buy the security before the security
has been issued. The Fund's payment obligation and the interest rate on the
security are determined when the Fund enters into the commitment. The security
is typically delivered to the Fund 15 to 120 days later. No interest accrues on
the security between the time the Fund enters into the commitment and the time
the security is issued. If the value of the security being purchased falls
between the time the Fund commits to buy it and the payment date, the Fund may
sustain a loss. The risk of this loss is in addition to the Fund's risk of loss
on the securities actually held in its portfolio at the time. When the Fund buys
a security on a when-issued basis, it is subject to the risk that market rates
of interest will increase before the time the security is delivered, with the
result that the yield on the security delivered to the Fund may be lower than
the yield available on other comparable securities at the time of delivery. If
the Fund has outstanding obligations to buy when-issued securities, it will
maintain liquid assets in a segregated account at its custodian bank in an
amount sufficient to satisfy these obligations.

FOREIGN SECURITIES
- ------------------

The Fund may invest in dollar-denominated securities of issuers organized
or headquartered outside the United States ("foreign securities"). The Fund will
not purchase a foreign security (for purposes of this limitation securities of
Canadian issuers publicly traded in the United States will not be treated as
foreign securities) if, as a result, the Fund's total holdings of foreign
securities would exceed 20% of the Fund's total assets. The Fund's portfolio
securities will principally trade on U.S. exchanges or will be purchased and
sold in U.S. markets.

Foreign securities may present risks not associated with investments in
comparable securities of U.S. issuers. There may be less information publicly
available about a foreign corporate or governmental issuer than about a U.S.
issuer, and foreign issuers are not generally subject to accounting, auditing
and financial reporting standards and practices comparable to those in the
United States. The securities of some foreign issuers are less liquid and at
times more volatile than securities of comparable U.S. issuers. Foreign
brokerage commissions and securities custody costs are often higher than in the
United States. With respect to certain foreign countries, there is a possibility
of governmental expropriation of assets, confiscatory taxation, political or
financial instability and diplomatic developments that could affect the value of
investments in those countries. The Fund's receipt of interest on foreign
government securities may depend on the availability of tax or other revenues to
satisfy the issuer's obligations. The remedies of the Fund may be extremely
limited if a foreign issuer defaults on its obligations. In addition, the
operations and results of foreign issuers and domestic issuers with operations
abroad may be affected by currency exchange rate fluctuations or exchange
control regulations.

9
<PAGE>

The Fund's investments in foreign securities may include investments in
countries whose economies or securities markets are not yet highly developed.
Special considerations associated with these investments (in addition to
considerations regarding foreign investments generally) may include, among
others, greater political uncertainties, an economy's dependence on revenues
from particular commodities or on international aid or development assistance,
currency transfer restrictions, highly limited numbers of potential buyers for
such securities and delays and disruptions in securities settlement procedures.

YEAR 2000
- ---------

Many computer software systems in use today cannot properly process date-
related information from and after January 1, 2000. Should any of the computer
systems employed by the Fund's major service providers fail to process this type
of information properly, that could have a negative impact on the Fund's
operations and the services that are provided to the Fund's shareholders. Loomis
Sayles has advised the Fund that it is reviewing all of its computer systems
with the goal of modifying or replacing such systems prior to January 1, 2000,
to the extent necessary to foreclose any such negative impact. In addition,
Loomis Sayles has been advised by the Fund's custodian that it is also in the
process of reviewing its systems with the same goal. As of the date of this
prospectus, the Fund and Loomis Sayles have no reason to believe that these
goals will not be achieved. Similarly, the values of certain of the portfolio
-------------------------------------------------
securities held by the Fund may be adversely affected by the inability of the
- -----------------------------------------------------------------------------
securities' issuers or of third parties to process this type of information
- ---------------------------------------------------------------------------
properly.
- --------

THE FUND'S INVESTMENT ADVISER

The Fund's investment adviser is Loomis Sayles, One Financial Center,
Boston, Massachusetts 02111. Founded in 1926, Loomis Sayles is one of the
country's oldest and largest investment firms. The general partner of Loomis
Sayles is a special purpose corporation that is an indirect wholly-owned
subsidiary of Nvest Companies, L.P. ("Nvest Companies"). Nvest Companies'
managing general partner, Nvest Corporation, is a direct wholly-owned subsidiary
of Metropolitan Life Insurance Company ("Met Life"), a mutual life insurance
company. Nvest Companies' advising general partner, Nvest, L.P., is a publicly
traded company listed on the New York Stock Exchange. Nvest Corporation is the
sole general partner of Nvest L.P.

In addition to selecting and reviewing the Fund's investments, Loomis
Sayles provides executive and other personnel for the management of the Fund.
The Trustees supervise Loomis Sayles's conduct of the affairs of the Fund.

The portfolio manager for the Fund since its inception has been William F.
Camp. Mr. Camp is a Vice President of Loomis Sayles and joined the firm in 1995.
Previously, Mr. Camp worked as a portfolio manager in the pension department of
Kmart Corporation.

FUND EXPENSES

The Fund pays Loomis Sayles a monthly investment advisory fee. This fee is
paid at the annual rate of .50% of the Fund's average daily net assets.

Loomis Sayles has voluntarily undertaken for an indefinite period to waive
its fees and, to the extent necessary, to bear other Fund expenses in order to
limit the Fund's annualized total operating expenses to .65% of average annual
net assets.

10
<PAGE>

PORTFOLIO TRANSACTIONS

Loomis Sayles selects brokers and dealers to execute portfolio transactions
for the Fund. Portfolio turnover considerations will not limit Loomis Sayles's
investment discretion in managing the Fund's assets. The Fund anticipates that
its portfolio turnover rates will vary significantly from time to time depending
on the volatility of economic and market conditions. High portfolio turnover may
result in higher costs such as higher brokerage commissions and higher levels of
taxable gains. Portfolio turnover rates for the life of the Fund are set forth
above under the headings "Financial Highlights" and "Prior Performance." See
"Dividends, Capital Gain Distributions and Taxes" for information on the tax
consequences of investing in the Fund.

HOW TO PURCHASE SHARES

You may make an initial purchase of shares of the Fund by submitting a
completed application form and payment to Loomis Sayles.

The minimum initial investment in the Fund is $1 million. Subsequent
investments must be at least $50,000. The Trust reserves the right to waive
these minimums in its sole discretion.

Shares of the Fund may be purchased by exchange of (i) cash, (ii)
securities on deposit with a custodian acceptable to Loomis Sayles or (iii) a
combination of such securities and cash. Purchase of shares of the Fund in
exchange for securities is subject in each case to the determination by Loomis
Sayles that the securities to be exchanged are acceptable for purchase by the
Fund. Securities accepted by Loomis Sayles in exchange for Fund shares will be
valued in the same manner as the Fund's assets, as described below, as of the
time of the Fund's next determination of net asset value after such acceptance.
All dividends and subscription or other rights which are reflected in the market
price of accepted securities at the time of valuation become the property of the
Fund and must be delivered to the Fund upon receipt by the investor from the
issuer. A gain or loss for federal income tax purposes would be realized upon
the exchange by an investor that is subject to federal income taxation,
depending upon the investor's basis in the securities tendered. A shareholder
who wishes to purchase shares by exchanging securities should obtain
instructions by calling (617) 482-2450.

Upon acceptance of your order, the Trust opens an account for you, applies
the payment to the purchase of full and fractional Fund shares and mails a
statement of the account confirming the transaction. After an account has been
established, you may send subsequent investments at any time.

The Trust reserves the right to reject any purchase order for any reason
which the Trust in its sole discretion deems appropriate. Although the Trust
does not anticipate that it will do so, the Trust reserves the right to suspend
or change the terms of the offering of its shares.

The price you pay will be the per share net asset value next calculated
after a proper investment order is received by the Trust. Shares of the Fund are
sold without any sales charge. The net asset value of the Fund's shares is
calculated by dividing the Fund's net assets by the number of shares
outstanding. The Fund intends to calculate net asset value daily and as of the
close of the New York Stock Exchange (the "Exchange") on each day on which an
order for purchase or redemption of Fund shares is received and on which the
Exchange is open for unrestricted trading. Portfolio securities are valued at
their market value as more fully described in the Statement of Additional
Information.

HOW TO REDEEM SHARES

You can redeem your shares by sending a written request to the Trust.

11
<PAGE>

written request in the exact names in which the shares are registered and should
indicate any special capacity in which they are signing (such as trustee or
custodian or on behalf of a partnership, corporation or other entity).

Proceeds resulting from a written redemption request will normally be
mailed to you within seven days after receipt of your request in good order. If
you purchased your shares by check and your check was deposited less than
fifteen days prior to the redemption request, the Trust may withhold redemption
proceeds until your check has cleared.

Redemption proceeds may be made in money or in kind, or partly in money and
partly in kind, as determined by the Trust.

The Fund may suspend the right of redemption and may postpone payment for
more than seven days when the Exchange is closed for other than weekends or
holidays, or if permitted by the rules of the SEC when trading on the Exchange
is restricted or during an emergency which makes it impracticable for the Fund
to dispose of its securities or to determine fairly the value of its net assets,
or during any other period permitted by the SEC for the protection of investors.

OTHER INFORMATION

The Trustees may, without shareholder approval, divide the Trust's shares
of beneficial interest into multiple series. The Trust is currently divided into
seven series, including the Fund and the other funds listed on the cover of this
Prospectus.

As of March 31, 1998, Asbestos Workers Local #84 Pension Plan may be deemed
to control the Fund because it possessed beneficial ownership, directly or
indirectly, of more than 25% of the Fund's shares.

The Fund's investment performance may from time to time be included in
advertisements about the Fund.

The Fund's yield will be computed by dividing the Fund's net investment
income for a recent 30-day period by the maximum offering price (reduced by any
undeclared earned income expected to be paid shortly as a dividend) on the last
trading day of that period.

Total return for the Fund is measured by comparing the value of an
investment in the Fund at the beginning of the relevant period to the redemption
value of the investment in the Fund at the end of the period (assuming immediate
reinvestment of any dividends or capital gain distributions).

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES

Because the Fund is designed primarily for tax-exempt investors such as
pension plans, endowments and foundations, the Fund is not managed with a view
to reducing taxes. The Fund pays any net investment income to shareholders as
dividends annually. The Fund also distributes all of its net realized capital
gains after applying any capital loss carryovers. Any capital gain distributions
are normally made annually in December, but may, to the extent permitted by law,
be made

12
<PAGE>

more frequently as deemed advisable by the Trustees. The Trustees may change the
frequency with which the Fund declares or pays dividends.

Your dividends and capital gain distributions will automatically be
reinvested in additional shares of the Fund on the payment date unless you have
elected to receive cash. Dividends and capital gain distributions will be taxed
as described below whether received in cash or in additional shares.

The Fund intends to qualify as a "regulated investment company" under the
Internal Revenue Code of 1986, as amended. As such, so long as the Fund
distributes all its net investment income and net realized capital gains to its
shareholders on a current basis, the Fund itself does not pay any federal income
or excise tax. The Fund intends to make sufficient distributions to be relieved
of federal taxes.

Income dividends and short-term capital gain distributions are treated as
ordinary income to you whether distributed in cash or additional shares.
Distributions designated by the Fund as deriving from net gains on securities
held for more than one year but not more than 18 months and from net gains on
securities held for more than 18 months will be taxable as such whether
distributed in cash or additional shares and regardless of how long you have
held your shares. However, any loss recognized by you on the taxable disposition
of shares held for six months or less will be treated as a long-term capital
loss to the extent of any long-term capital gain distribution you received with
respect to the shares.

The Fund is required to withhold 31% of redemption proceeds, income
dividends and capital gain distributions it pays to you (1) if you do not
provide a correct, certified taxpayer identification number, (2) if the Fund is
notified that you have underreported income in the past, or (3) if you fail to
certify to the Fund that you are not subject to such withholding.

In January of each year, the Trust will send you a statement showing the
federal tax status of dividends and distributions paid to you during the
preceding year.

The foregoing summarizes certain U.S. federal income tax consequences of
investing in the Fund. Before investing, you should consult your own tax adviser
for more information concerning the federal, foreign, state and local tax
consequences of investing in, redeeming or exchanging Fund shares.

TRANSFER AND DIVIDEND INVESTMENT ADVISER
PAYING AGENT AND Loomis, Sayles & Company, L.P.
CUSTODIAN OF ASSETS One Financial Center
State Street Bank and Trust Company Boston, Massachusetts 02111
Boston, Massachusetts 02102

13
<PAGE>

APPENDIX A

DESCRIPTION OF BOND RATINGS ASSIGNED BY
STANDARD & POOR'S AND
MOODY'S INVESTORS SERVICE, INC.

STANDARD & POOR'S
- -----------------

AAA

This is the highest rating assigned by Standard & Poor's to a debt obligation
and indicates an extremely strong capacity to pay interest and repay principal.

Bonds rated A have a strong capacity to pay interest and repay principal,
although they are somewhat more susceptible to the adverse effects of changes
in circumstances and economic conditions than obligations in higher rated
categories.

BBB

BB, B, CCC, CC

The rating C is reserved for income bonds on which no interest is being paid.

Bonds rated D are in default, and payment of interest and/or repayment of
principal is in arrears.

This symbol is attached to the ratings of instruments with significant
noncredit risks such as risks to principal or volatility of expected
returns.

Plus (+) or Minus (-): The ratings from "AA" to "B" may be modified by the
addition of a plus or minus sign to show relative standing within the major
rating categories.

14
<PAGE>

MOODY'S INVESTORS SERVICE, INC.
- -------------------------------

AAA

Bonds that are rated Aa are judged to be high quality by all standards. Together
with the Aaa group they comprise what are generally known as high grade bonds.
They are rated lower than the best bonds because margins of protection may not
be as large as in Aaa securities or fluctuation of protective elements may be of
greater amplitude or there are other elements present that make the long-term
risks appear somewhat larger than in Aaa securities.

BAA

Bonds that are rated Baa are considered as medium grade obligations; i.e., they
are neither highly protected nor poorly secured. Interest payments and principal
security appear adequate for the present, but certain protective elements may be
lacking or may be characteristically unreliable over any great length of time.
Such bonds lack outstanding investment characteristics and, in fact, have
speculative characteristics as well.

CAA

Bonds which are rated Caa are of poor standing. Such issues may be in default or
there may be present elements of danger with respect to principal or interest.

Bonds which are rated Ca represent obligations which are speculative in a high
degree. Such issues are often in default or have other marked shortcomings.

15
<PAGE>

Bonds which are rated C are the lowest rated class of bonds, and issues so rated
can be regarded as having extremely poor prospects of ever attaining any real
investment standing.

Should no rating be assigned by Moody's, the reason may be one of the following:

1. An application for rating was not received or accepted.

2. The issue or issuer belongs to a group of securities that
are not rated as a matter of policy.

3. There is lack of essential data pertaining to the issue or
issuer.

4. The issue was privately placed in which case the rating is
not published in Moody's publications.

16
<PAGE>

17
<PAGE>

LOOMIS SAYLES INVESTMENT TRUST

LOOMIS SAYLES CORE GROWTH FUND

ONE FINANCIAL CENTER
BOSTON, MASSACHUSETTS 02111
(617) 482-2450

PROSPECTUS

APRIL 22, 1998

The Loomis Sayles Investment Trust (the "Trust") is a group of seven mutual
funds including the Loomis Sayles Core Growth Fund (the "Fund"). The other
series, which are described in separate prospectuses, are:

Loomis Sayles California Tax-Free Income Fund
Loomis Sayles Core Fixed Income Fund
Loomis Sayles Fixed Income Fund
Loomis Sayles High Yield Fixed Income Fund
Loomis Sayles Intermediate Duration Fixed Income Fund
Loomis Sayles Investment Grade Fixed Income Fund

TABLE OF CONTENTS

<TABLE>
<S> <C>
SUMMARY OF EXPENSES............................................ -3-

FINANCIAL HIGHLIGHTS........................................... -4-

PRIOR PERFORMANCE.............................................. -5-

THE TRUST...................................................... -6-

INVESTMENT OBJECTIVE AND POLICIES.............................. -6-

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS.................. -6-

THE FUND'S INVESTMENT ADVISER.................................. -7-

FUND EXPENSES.................................................. -8-

PORTFOLIO TRANSACTIONS......................................... -8-

HOW TO PURCHASE SHARES......................................... -8-

HOW TO REDEEM SHARES........................................... -9-

OTHER INFORMATION.............................................. -9-

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES................ -10-
</TABLE>

2
<PAGE>

SUMMARY OF EXPENSES

<TABLE>
<S> <C>
Shareholder Transaction Expenses:
Maximum Sales Load Imposed on
Purchases (as a percentage of offering price) none
Maximum Sales Load Imposed on
Reinvested Dividends (as a percentage of
offering price) none
Deferred Sales Load (as a percentage of original
purchase price or redemption
proceeds as applicable) none
Redemption Fees (as a percentage of amount
redeemed) none
Exchange Fees none

Annual Fund Operating Expenses
(as a percentage of average net assets):
Management Fees (after expense
limitation) .50%
12b-1 Fees none
Other Operating Expenses/1/ .15%
Total Fund Operating Expenses (after
expense limitation)/1/ .65%

Example
You would pay the following
expenses on a $1,000 investment
assuming a 5% annual return
(with or without a redemption at
the end of each time period):

One Year $ 7
Three Years $21
Five Years $36
Ten Years $81
</TABLE>

<PAGE>

FINANCIAL HIGHLIGHTS

<TABLE>
<CAPTION>
March 7+ through
December 31, 1997
------------------
<S> <C>

Net asset value, beginning of period......................... $ 12.27

Income from investment operations -
Net investment income....................................... 0.07
Net realized and unrealized gain (loss) on investments...... 0.92
----------
Total from investment operations........................... 0.99

Less distributions -
Dividends from net investment income........................ (0.10)
Distributions from net realized capital gains............... (0.90)
----------
Total distributions........................................ (1.00)
----------
Net asset value, end of period............................... $ 12.26
==========

Total return (%)............................................. 8.2**
Net assets, end of period (000).............................. $ 38,544
Ratio of operating expenses to average net assets (%)........ 0.65*
Ratio of net investment income to average net assets (%)..... 0.81*
Portfolio turnover rate (%).................................. 91.1**
Average commission rate...................................... $0.0596***
Without giving effect to the voluntary expense limitations:
The ratio of operating expenses to average net assets
would have been (%)........................................ 0.90*
The net investment income per share would have been......... $ 0.05
</TABLE>

+Date of effectiveness of the Fund's registration statement under the Securities
Act of 1933, as amended.

*Annualized.

**Not annualized.

***For fiscal years beginning on or after September 1, 1995, the Fund is
required to disclose its average commission rate per share for trades upon which
commissions are charged. This rate generally does not reflect mark-ups, mark-
downs or spreads on shares traded on a principal basis.

4
<PAGE>

PRIOR PERFORMANCE

(FOR A SHARE OF THE FUND OUTSTANDING THROUGHOUT THE INDICATED PERIODS)

The information presented below, for the periods indicated, relates to
periods prior to the effectiveness of the Fund's registration statement under
the Securities Act of 1933, as amended (the "1933 Act"). The following
information should be read in conjunction with the financial highlights,
financial statements, and notes thereto that have been audited by Coopers &
Lybrand, L.L.P., independent accountants, whose report thereon appears in the
Fund's 1997 Annual Report, which is incorporated by reference into this
Prospectus and the Statement of Additional Information. The Fund is managed in a
manner that is in all material respects similar to the manner in which it was
managed prior to the effectiveness of its registration statement under the 1933
Act.

<TABLE>
<CAPTION>
October 1*
January 1, 1997 Year Ended
through March 6, December 31, December 31,
1997 1996 1995
----------- ------------ -------------
<S> <C> <C> <C>
Net asset value, beginning of period........................ $ 11.48 $ 10.02 $ 10.00

Income from investment operations -
Net investment income....................................... 0.03 0.10 0.02
Net realized and unrealized gain (loss) on investments...... 0.76 1.47 0.02
-------- --------- ---------
Total from investment operations.......................... 0.79 1.57 0.04
-------- --------- ---------

Less distributions -
Dividends from net investment income........................ 0.00 (0.11) (0.02)

Net asset value, end of period.............................. $ 12.27 $ 11.48 $ 10.02
======== ========= =========

Total return (%)............................................ 6.9*** 15.6 0.4***
Net assets, end of period (000)............................. $ 25,885 $ 21,906 $ 7,609
Ratio of operating expenses to average net assets (%)....... 0.65** 0.65 0.65**
Ratio of net investment income to
average net assets (%)................................... 1.21** 1.10 1.36**
Portfolio turnover rate (%)................................. 16.8*** 96.5 22.4***
Average commission rate..................................... 0.0557 + $0.0278 + -----
Without giving effect to the voluntary expense
limitation:
The ratio of operating expenses to
average net assets would have been (%)............. 0.83** 0.89 1.43**
The net investment income per share would have been.. $ 0.02 $ 0.08 $ 0.01
</TABLE>

* Commencement of operations.
**Annualized.

***Not annualized.

+For fiscal years beginning on or after September 1, 1995, the Fund is required
to disclose its average commission rate per share for trades upon which
commissions are charged. This rate generally does not reflect mark-ups, mark-
downs, or spreads on shares traded on a principal basis.

5
<PAGE>

THE TRUST

The Fund is a series of the Trust. The Trust is a diversified open-end
management investment company which was organized as a Massachusetts business
trust on December 23, 1993. The Trust is authorized to issue an unlimited number
of full and fractional shares of beneficial interest in multiple series. Shares
are freely transferable and entitle shareholders to receive dividends as
determined by the Trust's board of trustees (the "Trustees") and to cast a vote
for each share held (with a fractional vote for each fractional share held) at
shareholder meetings. The Trust does not generally hold shareholder meetings and
will do so only when required by law. Shareholders may call meetings to consider
removal of the Trustees.

INVESTMENT OBJECTIVE AND POLICIES

The Fund's investment objective is long-term growth of capital.

The Fund seeks to attain its objective by identifying, and investing in the
common stock of, companies that will report above average and better than
consensus earnings growth over several years. Under normal market conditions,
the Fund will invest at least 65% of its total assets in common stocks and other
equity securities. While this approach will often lead to investing in
"traditional" growth companies, it may also encompass investments in such areas
as revitalized industries, restructured companies and cyclically sensitive
companies at the early stages of an economic advance. In addition to superior
earnings prospects, the Fund looks for companies undergoing qualitative
improvement likely to result in an upgraded valuation. Although such companies
may present greater opportunity for capital appreciation, investors should be
aware that greater risk may be associated with investments in such companies
than with equity securities generally. The Fund may also invest in securities
issued or guaranteed by the U.S. Government, its authorities, agencies or
instrumentalities and certificates representing undivided interests in the
interest or principal of U.S. Treasury securities (collectively, "U.S.
Government Securities"), when-issued securities, convertible securities and zero
coupon bonds.

Some of the Fund's investment restrictions are "fundamental" and cannot be
changed without a majority vote of the Fund's shareholders. Such restrictions
include: (1) a restriction prohibiting the Fund from making loans; (2) a
restriction prohibiting the Fund from purchasing a security (other than U.S.
Government Securities) if, as a result, more than 25% of the Fund's total assets
(taken at current value) would be invested in any one industry; (3) a
restriction prohibiting the Fund from borrowing money in excess of 10% of its
total assets (taken at cost) or 5% of its total assets (taken at current value),
whichever is lower, and from borrowing any money except as a temporary measure
for extraordinary or emergency purposes; and (4) a restriction prohibiting the
Fund from purchasing any illiquid security including a security that is not
readily marketable if, as a result, more than 15% of the Fund's net assets based
on current value would then be invested in such securities. For additional
investment restrictions, see the Statement of Additional Information.

Although authorized to invest in restricted securities, the Fund, as a
matter of nonfundamental operating policy, currently does not intend to invest
in such securities, other than Rule 144A securities. Rule 144A securities are
privately offered securities that can be resold only to certain qualified
institutional buyers. Rule 144A securities are treated as illiquid, unless
Loomis Sayles has determined, under guidelines established by the Trustees, that
the particular issue of Rule 144A securities is liquid.

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS

6
<PAGE>

The net asset value of the Fund's shares will vary as a result of changes
in the value of securities in the Fund's portfolio. The following describes the
securities in which the Fund will principally invest and the risks associated
with them. Additional information about the Fund's investment practices can be
found in the Statement of Additional Information.

EQUITY SECURITIES
- -----------------

While offering greater potential for long-term growth, equity securities
are more volatile and more risky than some other forms of investment. The Fund's
investments may include securities traded "over-the-counter" as well as those
traded on a securities exchange. Some over-the-counter securities may be more
difficult to sell under some market conditions.

SMALL COMPANIES
- ---------------

The Fund may invest in the securities of companies with smaller
capitalization. Investments in companies with relatively small capitalization
may involve greater risk than is usually associated with more established
companies. These companies often have sales and earnings growth rates which
exceed those of companies with larger capitalization. Such growth rates may in
turn be reflected in more rapid share price appreciation. However, companies
with smaller capitalization often have limited product lines, markets or
financial resources and they may be dependent upon a relatively small management
group. The securities may have limited marketability and may be subject to more
abrupt or erratic movements in price than securities of companies with larger
capitalization or the market averages in general. The net asset value of funds
that invest in companies with small capitalization therefore may fluctuate more
widely than market averages.

WHEN-ISSUED SECURITIES
- ----------------------

The Fund may purchase securities on a "when-issued" basis. This means that
the Fund will enter into a commitment to buy the security before the security
has been issued. The Fund's payment obligation and the interest rate on the
security are determined when the Fund enters into the commitment. The security
is typically delivered to the Fund 15 to 120 days later. No interest accrues on
the security between the time the Fund enters into the commitment and the time
the security is issued. If the value of the security being purchased falls
between the time a Fund commits to buy it and the payment date, the Fund may
sustain a loss. The risk of this loss is in addition to the Fund's risk of loss
on the securities actually in its portfolio at the time. If the Fund has
outstanding obligations to buy when-issued securities, it will maintain liquid
assets in a segregated account at its custodian bank in an amount sufficient to
satisfy these obligations.

YEAR 2000
- ---------

Many computer software systems in use today cannot properly process
date-related information from and after January 1, 2000. Should any of the
computer systems employed by the Fund's major service providers fail to process
this type of information properly, that could have a negative impact on the
Fund's operations and the services that are provided to the Fund's shareholders.
Loomis Sayles has advised the Fund that it is reviewing all of its computer
systems with the goal of modifying or replacing such systems prior to January 1,
2000, to the extent necessary to foreclose any such negative impact. In
addition, Loomis Sayles has been advised by the Fund's custodian that it is also
in the process of reviewing its systems with the same goal. As of the date of
this prospectus, the Fund and Loomis Sayles have no reason to believe that these
goals will not be achieved. Similarly, the values of certain of the portfolio
-------------------------------------------------
securities held by the Fund may be adversely affected by the inability of the
- -----------------------------------------------------------------------------
securities' issuers or of third parties to process this type of information
- ---------------------------------------------------------------------------
properly.
- ---------

THE FUND'S INVESTMENT ADVISER

The Fund's investment adviser is Loomis Sayles, One Financial Center,
Boston, Massachusetts 02111. Founded in 1926, Loomis Sayles is one of the
country's oldest and largest investment firms.

7
<PAGE>

The general partner of Loomis Sayles is a special purpose corporation that
is an indirect wholly-owned subsidiary of Nvest Companies, L.P. ("Nvest
Companies"). Nvest Companies' managing general partner, Nvest Corporation, is a
direct wholly-owned subsidiary of Metropolitan Life Insurance Company ("Met
Life"), a mutual life insurance company. Nvest Companies' advising general
partner, Nvest, L.P., is a publicly traded company listed on the New York Stock
Exchange. Nvest Corporation is the sole general partner of Nvest L.P.

In addition to selecting and reviewing the Fund's investments, Loomis
Sayles provides executive and other personnel for the management of the Fund.
The Board of Trustees supervises Loomis Sayles's conduct of the affairs of the
Fund.

The portfolio manager for the Fund since inception has been Quentin P.
Faulkner. Mr. Faulkner is a Vice President of Loomis Sayles and a Managing
Partner of its Boston Counseling Group office.

FUND EXPENSES

The Fund pays Loomis Sayles a monthly investment advisory fee. This fee is
paid at the annual rate of .50% of the Fund's average daily net assets.

Loomis Sayles has voluntarily undertaken for an indefinite period to waive
its fees and, to the extent necessary, to bear other Fund expenses in order to
limit the Fund's total operating expenses to .65% of average annual net assets.

PORTFOLIO TRANSACTIONS

Loomis Sayles selects brokers and dealers to execute portfolio transactions
for the Fund. Portfolio turnover considerations will not limit Loomis Sayles's
investment discretion in managing the Fund's assets. The Fund anticipates that
its portfolio turnover rates will vary significantly from time to time depending
on the volatility of economic and market conditions. High portfolio turnover may
result in higher costs such as higher brokerage commissions and higher levels of
taxable gains. Portfolio turnover rates for the life of the Fund are set forth
above under the headings "Financial Highlights" and "Prior Performance." See
"Dividends, Capital Gain Distributions and Taxes" for information on the tax
consequences of investing in the Fund.

HOW TO PURCHASE SHARES

You may make an initial purchase of shares of the Fund by submitting a
completed application form and payment to Loomis Sayles. The minimum initial
investment in the Fund is $2,500,000. Subsequent investments must be at least
$50,000. The Trust reserves the right to waive these minimums in its sole
discretion.

Shares of the Fund may be purchased by exchange of (i) cash, (ii)
securities on deposit with a custodian acceptable to Loomis Sayles or (iii) a
combination of such securities and cash. Purchase of shares of the Fund in
exchange for securities is subject in each case to the determination by Loomis
Sayles that the securities to be exchanged are acceptable for purchase by the
Fund. Securities accepted by Loomis Sayles in exchange for Fund shares will be
valued in the same manner as the Fund's assets, as described below, as of the
time of the Fund's next determination of net asset value after such acceptance.
All dividends and subscription or other rights which are reflected in the market
price of accepted securities at the time of valuation become the property of the
Fund and must be delivered to the Fund upon receipt by the investor from the
issuer. A gain or loss for federal income tax purposes would be realized upon
the exchange of any securities tendered. A shareholder who wishes to purchase
shares by exchanging securities should obtain instructions by calling (617) 482-
2450.

8
<PAGE>

Upon acceptance of your order, the Trust opens an account for you, applies
the payment to the purchase of full and fractional Fund shares and mails a
statement of the account confirming the transaction. After an account has been
established, you may send subsequent investments at any time.

The Trust reserves the right to reject any purchase order for any reason
which the Trust in its sole discretion deems appropriate. Although the Trust
does not anticipate that it will do so, the Trust reserves the right to suspend
or change the terms of the offering of its shares.

The price you pay will be the per share net asset value next calculated
after a proper investment order is received by the Trust. Shares of the Fund are
sold without any sales charge. The net asset value of the Fund's shares is
calculated by dividing the Fund's net assets by the number of shares
outstanding. Net asset value is calculated at least weekly and as of the close
of the New York Stock Exchange (the "Exchange") on each day on which an order
for purchase or redemption of Fund shares is received and on which the Exchange
is open for unrestricted trading. Portfolio securities are valued at their
market value as more fully described in the Statement of Additional Information.

HOW TO REDEEM SHARES

You can redeem your shares by sending a written request to the Trust.

Proceeds resulting from a written redemption request will normally be
mailed to you within seven days after receipt of your request in good order. If
you purchased your shares by check and your check was deposited less than
fifteen days prior to the redemption request, the Trust may withhold redemption
proceeds until your check has cleared.

Redemption proceeds may be made in money or in kind, or partly in money and
partly in kind, as determined by the Trust.

The Fund may suspend the right of redemption and may postpone payment for
more than seven days when the Exchange is closed for other than weekends or
holidays, or if permitted by the rules of the SEC when trading on the Exchange
is restricted or during an emergency which makes it impracticable for the Fund
to dispose of its securities or to determine fairly the value of its net assets,
or during any other period permitted by the SEC for the protection of investors.

OTHER INFORMATION

The Board of Trustees may, without shareholder approval, divide the Trust's
shares of beneficial interest into multiple series. The Trust is currently
divided into seven series, including the Fund and the other funds listed on the
cover of this Prospectus.

9
<PAGE>

As of March 31, 1998, Brockton Health Corp. Endowment may be deemed to
control the Fund because it possessed beneficial ownership, either directly or
indirectly, of more than 25% of the Fund's shares.

The Fund's investment performance may from time to time be included in
advertisements about the Fund.

Total return for the Fund is measured by comparing the value of an
investment in the Fund at the beginning of the relevant period to the redemption
value of the investment in the Fund at the end of the period (assuming immediate
reinvestment of any dividends or capital gain distributions).

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES

Because the Fund is designed primarily for tax-exempt investors such as
pension plans, endowments and foundations, the Fund is not managed with a view
to reducing taxes. The Fund pays any net investment income to shareholders as
dividends annually. Any capital gain distributions are normally made annually in
December, but may, to the extent permitted by law, be made more frequently as
deemed advisable by the Trustees. The Fund distributes all of its net realized
capital gains after applying any capital loss carryovers. The Trustees may
change the frequency with which the Fund declares or pays dividends.

The Fund intends to qualify as a "regulated investment company" under the
Internal Revenue Code of 1986, as amended. As such, so long as the Fund
distributes substantially all its net investment income and net realized capital
gains to its shareholders on a current basis, the Fund itself does not pay any
federal income or excise tax. The Fund intends to make sufficient distributions
to be relieved of federal taxes.

Income dividends and short-term capital gain distributions are treated as
ordinary income to you whether distributed in cash or additional shares.
Distributions designated by the Fund as deriving from net gains on securities
held for more than one year but not more than 18 months and from net gains on
securities held for more than 18 months will be taxable as such whether
distributed in cash or additional shares and regardless of how long you have
held your shares. However, any loss recognized by you on the taxable disposition
of shares held for six months or less will be treated as a long-term capital
loss to the extent of any capital gain distribution you received with respect to
the shares.

A portion of any dividend from the Fund is expected to be eligible for the
dividends-received deduction for corporate shareholders.

The Trust will send you an annual statement showing the federal tax status
of dividends and distributions paid to you during the preceding year.

10
<PAGE>

11
<PAGE>

LOOMIS SAYLES INVESTMENT TRUST

LOOMIS SAYLES FIXED INCOME FUND

ONE FINANCIAL CENTER
BOSTON, MASSACHUSETTS 02111
(617) 482-2450

PROSPECTUS

APRIL 22, 1998

The Loomis Sayles Investment Trust (the "Trust") is a group of seven mutual
funds including the Loomis Sayles Fixed Income Fund (the "Fund"). The other
series, which are described in separate prospectuses, are:

Loomis Sayles California Tax-Free Income Fund
Loomis Sayles Core Fixed Income Fund
Loomis Sayles Core Growth Fund
Loomis Sayles High Yield Fixed Income Fund
Loomis Sayles Intermediate Duration Fixed Income Fund
Loomis Sayles Investment Grade Fixed Income Fund

TABLE OF CONTENTS

<TABLE>
<S> <C>
SUMMARY OF EXPENSES...................................................... -3-

FINANCIAL HIGHLIGHTS..................................................... -4-

PRIOR PERFORMANCE........................................................ -5-

THE TRUST................................................................ -6-

INVESTMENT OBJECTIVE AND POLICIES........................................ -6-

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS............................ -7-

THE FUND'S INVESTMENT ADVISER............................................ -11-

FUND EXPENSES............................................................ -12-

PORTFOLIO TRANSACTIONS................................................... -12-

HOW TO PURCHASE SHARES................................................... -12-

HOW TO REDEEM SHARES..................................................... -13-

OTHER INFORMATION........................................................ -13-

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES.......................... -14-

APPENDIX A............................................................... A-1
</TABLE>

-2-
<PAGE>

SUMMARY OF EXPENSES

<TABLE>
<S> <C>
Shareholder Transaction Expenses:
Maximum Sales Load Imposed on
Purchases (as a percentage of offering price) none
Maximum Sales Load Imposed on
Reinvested Dividends (as a percentage of
offering price) none
Deferred Sales Load (as a percentage of
original purchase price or redemption
proceeds, as applicable) none
Redemption Fees (as a percentage of
amount redeemed) none
Exchange Fees none

Annual Fund Operating Expenses
(as a percentage of average net assets):
Management Fees (after expense limitation)/1/ .50%

12b-1 Fees none
Other Operating Expenses (after expense limitation)/1/ .15%
Total Fund Operating Expenses (after expense limitation)/1/ .65%
</TABLE>

<TABLE>
<S> <C>
Example
You would pay the following
expenses on a $1,000 investment
assuming a 5% annual return
(with or without a redemption at
the end of each time period):

One Year $ 7
Three Years $ 21
Five Years $ 36
Ten Years $ 81
</TABLE>

_____________________
/1/ Loomis Sayles has voluntarily undertaken for an indefinite period to
limit the Fund's total Fund operating expenses to the percentage of average net
assets shown above. In the absence of the voluntary expense limitation, Other
Operating Expenses and Total Fund Operating Expenses for the fiscal year ended
December 31, 1997 would have been 0.20% and 0.70%, respectively.

-3-
<PAGE>

FINANCIAL HIGHLIGHTS

The financial highlights table that follows is for the period March 7,
1997 through December 31, 1997. The following information should be read in
conjunction with the financial highlights, financial statements, and notes
thereto that have been audited by Coopers & Lybrand, L.L.P., independent
accountants, whose report thereon appears in the Fund's 1997 Annual Report,
which is incorporated by reference into this Prospectus and the Statement of
Additional Information.

<TABLE>
<CAPTION>
March 7+ through
December 31, 1997
-----------------
<S> <C>
Net asset value, beginning of period......................... $ 12.26

Income from investment operations -
Net investment income....................................... 0.53
Net realized and unrealized gain (loss) on investments...... 0.90
--------
Total from investment operations........................... 1.43

Less distributions -
Dividends from net investment income........................ (0.75)
Distributions from net realized capital gains............... (0.35)
--------
Total distributions........................................ (1.10)
Net asset value, end of period............................... $ 12.59
========

Total return (%)............................................. 11.7**
Net assets, end of period (000).............................. $173,048
Ratio of operating expenses to average net assets (%)........ 0.65*
Ratio of net investment income to average net assets (%)..... 7.31*
Portfolio turnover rate (%).................................. 38.2**
Without giving effect to the voluntary expense limitations:
The ratio of operating expenses to average net assets
would have been (%)........................................ 0.71*
The net investment income per share would have been.......... $ 0.53
</TABLE>

+Date of effectiveness of the Fund's registration statement under the
Securities Act of 1933, as amended.
*Annualized.
**Not annualized.

Further information about the performance of the Fund is contained in
the Fund's semiannual and annual reports to shareholders, copies of which may be
obtained without charge by writing or telephoning the Trust at the address and
telephone number stated on the cover of this Prospectus.

-4-
<PAGE>

PRIOR PERFORMANCE

(FOR A SHARE OF THE FUND OUTSTANDING THROUGHOUT THE INDICATED PERIODS)

<TABLE>
<CAPTION>
January 17*
January 1, 1997 Year Ended through
through March 6, December 31, December 31,
1997 1996 1995
----------------- ------------- ------------
<S> <C> <C> <C>
Net asset value, beginning of period....................... $ 12.08 $ 12.08 $ 10.00

Income from investment operations -
Net investment income................................... 0.19 0.91 0.53
Net realized and unrealized gain (loss) on investments.. (0.01) 0.27 2.21
------- ------- -------
Total from investment operations...................... 0.18 1.18 2.74
------- ------- -------

Less distributions -
Dividends from net investment income.................... 0.00 (0.90) (0.52)
Distributions from net realized capital gains........... 0.00 (0.28) (0.14)
------- ------- -------
Total distributions................................... 0.00 (1.18) (0.66)
------- ------- -------
Net asset value, end of period............................. $ 12.26 $ 12.08 $ 12.08
======= ======= =======

Total return (%)........................................... 1.5*** 9.8 27.4***
Net assets, end of period (000)............................ $97,132 $91,746 $58,332
Ratio of operating expenses to average net assets (%)...... 0.65** 0.62 0.75**
Ratio of net investment income to
average net assets (%).................................. 9.00** 7.97 8.15**
Portfolio turnover rate (%)................................ 2.2*** 90.4 76.0***
Without giving effect to the voluntary expense
limitation:
The ratio of operating expenses to
average net assets would have been (%)............... 0.65** 0.62 0.83**
The net investment income per share would have been.... $ 0.19 $ 0.91 $ 0.52
</TABLE>

-5-
<PAGE>

*Commencement of operations.
**Annualized.
***Not annualized.

THE TRUST

The Fund is a series of the Trust. The Trust is a diversified open-
end management investment company which was organized as a Massachusetts
business trust on December 23, 1993. The Trust is authorized to issue an
unlimited number of full and fractional shares of beneficial interest in
multiple series. Shares are freely transferable and entitle shareholders to
receive dividends as determined by the Trust's board of trustees (the
"Trustees") and to cast a vote for each share held (with a fractional vote for
each fractional share held) at shareholder meetings. The Trust does not
generally hold shareholder meetings and will do so only when required by law.
Shareholders may call meetings to consider removal of the Trustees.

INVESTMENT OBJECTIVE AND POLICIES

The Fund's investment objective is high total investment return
through a combination of current income and capital appreciation.

The Fund seeks to attain its objective by normally investing
substantially all of its assets in a broad range of debt securities, although up
to 20% of its assets may be invested in preferred stocks. These debt securities
may include corporate securities, securities issued or guaranteed by the U.S.
Government, its authorities, agencies or instrumentalities or certificates
representing undivided interests in the interest or principal of U. S. Treasury
securities ("U.S. Government Securities"), zero coupon securities,
collateralized mortgage securities, interest-only and principal-only ("IOs" and
"POs") classes of stripped mortgage-backed securities, convertible bonds and
when-issued securities, which are described herein (together with their related
risks) under "More Information About the Fund's Investments." Under normal
market conditions, the Fund will invest at least 65% of its total assets in
fixed income securities. The Fund may invest any portion of its assets in
securities of Canadian issuers, and a limited portion of its assets in
securities of other foreign issuers. See "More Information About the Fund's
Investments; Foreign Securities."

The Fund may invest up to 35% of its assets in securities of below
investment grade quality, which are securities rated below BBB by Standard &
Poor's ("S&P") and below Baa by Moody's Investors Service, Inc. ("Moody's"), and
in unrated securities determined by Loomis Sayles to be of comparable quality.
Securities of below investment grade quality are commonly referred to as "junk
bonds." See "More Information About the Fund's Investments; Lower Rated Fixed
Income Securities." The Fund may continue to hold securities that are
downgraded in quality subsequent to their purchase if, in the opinion of Loomis
Sayles, it would be advantageous to do so.

The percentages of the Fund's net assets invested during the fiscal year ended
December 31, 1997 in securities assigned to the various rating categories by S&P
and Moody's on a dollar-weighted basis were approximately as follows: "AAA"/
"Aaa," 19.7%; "AA"/"Aa," 7.5%; "A"/"A," 13.1%; "BBB"/"Baa," 29.0%; "BB"/"Ba,"
21.0%; "B"/"B," 9.7%; and below "B," 0%. The percentage of the Fund's net
assets invested during such fiscal year in unrated debt securities as a group
was approximately 1.47%. The percentages of the Fund's net assets invested
during such fiscal year in such unrated securities (categorized by comparable
rating category) were approximately as follows: "AAA"/"Aaa," 0%; "AA"/"Aa," 0%;
"A"/"A," 0.06%; "BBB"/"Baa," 0.29%; "BB"/"Ba," 1.12%; "B"/"B," 0%; and below
"B," 0%.

Some of the Fund's investment restrictions are "fundamental" and
cannot be changed without a majority vote of the Fund's shareholders. Such
restrictions include: (1) a restriction prohibiting the Fund from making loans;
(2) a restriction prohibiting the Fund from purchasing a security (other than
U.S. Government Securities) if, as a result, more than 25% of the Fund's total
assets (taken at current value) would be invested in any one industry; (3) a
restriction prohibiting the Fund from borrowing money in excess of 10% of its
total assets (taken at cost) or 5% of its total assets (taken at current value),
whichever is lower, and from borrowing any money except as a temporary measure
for extraordinary or emergency purposes; and (4) a restriction prohibiting the
Fund from purchasing any illiquid security including a security that is not
readily marketable if, as a result, more than 15% of the Fund's net assets based
on current

-6-
<PAGE>

value would then be invested in such security. For additional investment
restrictions, see the Statement of Additional Information.

The investment objective of the Fund is "fundamental" and cannot be
changed without a majority vote of the Fund's shareholders. All investment
policies other than those that are identified as "fundamental" may be changed by
the Trustees without a vote of the Fund's shareholders.

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS

The net asset value of the Fund's shares will vary as a result of
changes in the value of securities in the Fund's portfolio. The following
describes the types of securities in which the Fund will principally invest and
the risks associated with them. Additional information about the Fund's
investment practices can be found in the Statement of Additional Information.

FIXED INCOME SECURITIES
- -----------------------

Fixed income securities are subject to market and credit risk. Market
risk relates to changes in a security's value as a result of changes in interest
rates generally. In general, the values of fixed income securities increase
when prevailing interest rates fall and decrease when interest rates rise.
Credit risk relates to the ability of the issuer to make payments of principal
and interest. Generally, the longer the maturity of a fixed income security,
the greater the fluctuations in its value because of market and credit risk.

U.S. GOVERNMENT SECURITIES
- --------------------------

U.S. Government Securities have different kinds of government support.
For example, some U.S. Government Securities, such as U.S. Treasury bonds, are
supported by the full faith and credit of the United States, whereas certain
other U.S. Government Securities issued or guaranteed by federal agencies or
government-sponsored enterprises are not supported by the full faith and credit
of the United States.

Although U.S. Government Securities generally do not involve the credit
risks associated with other types of fixed income securities, the market values
of U.S. Government Securities will fluctuate as interest rates change. Thus,
for example, the value of an investment in U.S. Government Securities may fall
during times of rising interest rates. Yields on U.S. Government Securities tend
to be lower than those of other fixed income securities of comparable
maturities.

-7-
<PAGE>

real property. Interest and principal payments on the mortgages underlying
mortgage-backed U.S. Government Securities are passed through to the holders of
the security. If the Fund purchases mortgage-backed securities at a discount or
a premium, the Fund will recognize a gain or loss when the payments of
principal, through prepayment or otherwise, are passed through to the Fund and,
if the payment occurs in a period of falling interest rates, the Fund may not be
able to reinvest the payment at as favorable an interest rate. As a result of
these principal prepayment features, mortgage-backed securities are generally
more volatile investments than many other fixed income securities. See
"Collateralized Mortgage Obligations" below for additional information regarding
the risks associated with mortgage-backed securities.

In addition to investing directly in U.S. Government Securities, the Fund
may purchase certificates of accrual or similar instruments ("strips")
evidencing undivided ownership interests in interest payments or principal
payments, or both, in U.S. Treasury securities. These investment instruments
may be highly volatile.

ZERO COUPON SECURITIES
- ----------------------

COLLATERALIZED MORTGAGE OBLIGATIONS
- -----------------------------------

The Fund may invest in collateralized mortgage obligations ("CMOs"). A CMO
is a limited recourse security backed by a portfolio of mortgages or, more
typically, by mortgage-backed securities held under an indenture. CMOs may be
issued by instrumentalities of the U.S. Government or by non-governmental
entities. The issuer's obligation to make interest and principal payments is
derived from and secured by the underlying portfolio of mortgages or mortgage-
backed securities. CMOs are issued with a number of classes or series which
have different maturities and which may represent interests in some or all of
the interest or principal payments on the underlying collateral or a combination
thereof. CMOs of different classes or series are generally retired in sequence
as the underlying mortgage loans in the mortgage pool are repaid. In the event
of sufficient early prepayments on such mortgages, the class or series of CMOs
first to mature generally will be retired prior to its maturity. As with other
mortgage-backed securities, the early retirement of a particular class or series
of CMOs held by the Fund could involve the loss of any premium the Fund paid
when it acquired the investment and could result in the Fund's reinvesting the
proceeds at a lower interest rate than the interest rate paid by the retired
CMO. Because of the early retirement feature, CMOs may be more volatile than
many other fixed income investments. In addition, slower than anticipated
prepayments on the underlying mortgages can extend the effective maturities of
CMOs, subjecting them to a greater risk of decline in market value in response
to rising interest rates than traditional debt securities.

COMMERCIAL MORTGAGE-BACKED SECURITIES
- -------------------------------------

Commercial mortgage-backed securities are generally structured similarly to
pass-through securities or to CMOs, although other structures are possible.
They may pay fixed or adjustable rates of interest. Commercial mortgage-backed
securities have been issued in public or private transactions by a variety of
public and private issuers.

-8-
<PAGE>

The commercial mortgage loans that underlie commercial mortgage-backed
securities have certain distinct risk characteristics. Commercial mortgage
loans generally lack standardized terms, which may complicate their structure.
Commercial properties themselves tend to be unique and are more difficult to
value than single-family residential properties. Commercial mortgage loans also
tend to have shorter maturities than residential mortgage loans, and may not be
fully amortizing, meaning that they have a significant principal balance, or
"balloon" payment, due on maturity. Assets underlying commercial mortgage-backed
securities may relate only to a few properties or a single property. The risk
involved in single property financings is highly concentrated. In addition,
commercial properties, particularly industrial and warehouse properties, are
subject to environmental risks and the burdens and costs of compliance with
environmental laws and regulations. At the same time, commercial mortgage-backed
securities may have a lower prepayment risk than residential mortgage-backed
securities, because commercial mortgage loans generally prohibit or impose
penalties on prepayments of principal. In addition, commercial mortgage-backed
securities often are structured with some form of credit enhancement to protect
against potential losses on the underlying mortgage loans.

STRIPPED MORTGAGE-BACKED SECURITIES
- -----------------------------------

CONVERTIBLE SECURITIES
- ----------------------

Convertible securities include corporate bonds, notes or preferred stocks
of U.S. or foreign issuers that can be converted into (that is, exchanged for)
common stocks or other equity securities at a stated price or rate. Convertible
securities also include other securities, such as warrants, that provide an
opportunity for equity participation. Because convertible securities can be
converted into equity securities, their value will normally vary in some
proportion with those of the underlying equity securities. Convertible
securities usually provide a higher yield than the underlying equity security,
however, so that when the price of the underlying equity security falls, the
decline in the price of the convertible security may sometimes be less
substantial than that of the underlying equity security. Due to the conversion
feature, convertible securities generally yield less than nonconvertible
securities of similar credit quality and maturity. The Fund's investments in
convertible securities may at times include securities that have a mandatory
conversion feature, pursuant to which the securities convert automatically into
common stock at a specified date and conversion ratio, or that are convertible
at the option of the issuer. Because conversion of such securities is not at
the option of the holder, the Fund may be required to convert the security into
the underlying common stock even at times when the value of the underlying
common stock has declined substantially.

WHEN-ISSUED SECURITIES
- ----------------------

-9-
<PAGE>

to the risk that market rates of interest will increase before the time the
security is delivered, with the result that the yield on the security delivered
to the Fund may be lower than the yield available on other, comparable
securities at the time of delivery. If the Fund has outstanding obligations to
buy when-issued securities, it will maintain liquid assets in a segregated
account at its custodian bank in an amount sufficient to satisfy these
obligations.

LOWER RATED FIXED INCOME SECURITIES
- -----------------------------------

The Fund may invest a portion of its assets in securities rated below
investment grade ("lower rated fixed income securities"), including securities
in the lowest rating categories, and unrated securities determined by Loomis
Sayles to be of comparable quality. Lower rated fixed income securities
generally provide higher yields, but are subject to greater credit and market
risk than higher quality fixed income securities. Lower rated fixed income
securities are considered speculative with respect to the ability of the issuer
to meet principal and interest payments. Achievement of the Fund's investment
objective through investments in lower rated fixed income securities may be more
dependent on Loomis Sayles's credit analysis than is the case with higher
quality bonds. The market for lower rated fixed income securities may be more
severely affected than other financial markets by economic recession or
substantial interest rate increases. The value and liquidity of lower rated
fixed income securities may be diminished by adverse publicity and investor
perceptions. In addition, legislation that limits the tax benefits to issuers
or holders of taxable lower rated fixed income securities or that limits the
ability of certain categories of financial institutions to invest in these
securities may adversely affect their market value. The secondary market for
lower rated fixed income securities may be less liquid than the secondary market
for higher rated fixed income securities. This lack of liquidity at certain
times may affect the values of these securities and may make the valuation and
sale of these securities by the Fund more difficult. Certain lower rated fixed
income securities do not pay interest on a current basis. However, the Fund
will accrue and distribute this interest on a current basis, and may be required
to sell securities at times when Loomis Sayles would not otherwise deem it
advisable to do so in order to generate cash for distributions. Securities of
below investment grade quality are commonly referred to as "junk bonds."
Securities in the lowest rating categories may be in poor standing or in
default. Investment grade fixed income securities may share some of the
characteristics of lower rated fixed income securities described above.

FOREIGN SECURITIES
- ------------------

The Fund may invest in securities of issuers organized or headquartered
outside the United States ("foreign securities"). The Fund will not purchase a
foreign security (for purposes of this limitation securities of Canadian issuers
publicly traded in the United States will not be treated as foreign securities)
if, as a result, the Fund's total holdings of foreign securities would exceed
20% of the Fund's total assets.

Foreign securities may present risks not associated with investments in
comparable securities of U.S. issuers. There may be less information publicly
available about a foreign corporate or governmental issuer than about a U.S.
issuer, and foreign issuers are not generally subject to accounting, auditing
and financial reporting standards and practices comparable to those in the
United States. The securities of some foreign issuers are less liquid and at
times more volatile than securities of comparable U.S. issuers. Foreign
brokerage commissions and securities custody costs are often higher than in the
United States. With respect to certain foreign countries, there is a
possibility of governmental expropriation of assets, confiscatory taxation,
political or financial instability and diplomatic developments that could affect
the value of investments in those countries. The Fund's receipt of interest on
foreign government securities may depend on the availability of tax or other
revenues to satisfy the issuer's obligations. In addition, the remedies of the
Fund may be extremely limited if a foreign issuer defaults on its obligations.

-10-
<PAGE>

currency transfer restrictions, highly limited numbers of potential buyers for
such securities and delays and disruptions in securities settlement procedures.

Since most foreign securities are denominated in foreign currencies or
traded primarily in securities markets in which settlements are made in foreign
currencies, the value of these investments and the net investment income
available for distribution to shareholders of the Fund may be affected favorably
or unfavorably by changes in currency exchange rates or exchange control
regulations and foreign withholding taxes. Changes in the value relative to the
U.S. dollar of a foreign currency in which the Fund's holdings are denominated
will result in a change in the U.S. dollar value of the Fund's assets and the
Fund's income available for distribution.

In addition, although part of the Fund's income may be received or realized
in foreign currencies, the Fund will be required to compute and distribute its
income in U.S. dollars. Therefore, if the value of a currency relative to the
U.S. dollar declines after the Fund's income has been earned in that currency,
translated into U.S. dollars and declared as a dividend, but before payment of
the dividend, the Fund could be required to liquidate portfolio securities to
pay the dividend. Similarly, if the value of a currency relative to the U.S.
dollar declines between the time the Fund accrues expenses in U.S. dollars and
the time such expenses are paid, the amount of such currency required to be
converted into U.S. dollars will be greater than the equivalent amount in such
currency of such expenses at the time they were incurred.

YEAR 2000
- ---------

THE FUND'S INVESTMENT ADVISER

The Fund's investment adviser is Loomis Sayles, One Financial Center,
Boston, Massachusetts 02111. Founded in 1926, Loomis Sayles is one of the
country's oldest and largest investment firms.

In addition to selecting and reviewing the Fund's investments, Loomis
Sayles provides executive and other personnel for the management of the Fund.
The Board of Trustees supervises Loomis Sayles's conduct of the affairs of the
Fund.

-11-
<PAGE>

The portfolio manager for the Fund since its inception has been Daniel J.
Fuss, who has been with Loomis Sayles since 1976 and is head of the Fixed Income
Management Group. Mr. Fuss is an Executive Vice President and Director of
Loomis Sayles.

FUND EXPENSES

The Fund pays Loomis Sayles a monthly investment advisory fee. This fee is
paid at the annual rate of 0.50% of the Fund's average daily net assets.

Loomis Sayles has voluntarily undertaken for an indefinite period to waive
its fees and, to the extent necessary, to bear other Fund expenses in order to
limit the Fund's total operating expenses to .65% of average annual net assets.

PORTFOLIO TRANSACTIONS

HOW TO PURCHASE SHARES

You may make an initial purchase of shares of the Fund by submitting a
completed application form and payment to Loomis Sayles.

The minimum initial investment in the Fund is $3,000,000. Subsequent
investments must be at least $50,000. The Trust reserves the right to waive
these minimums in its sole discretion.

Shares of the Fund may be purchased by exchange of (i) cash, (ii)
securities on deposit with a custodian acceptable to Loomis Sayles or (iii) a
combination of such securities and cash. Purchase of shares of the Fund in
exchange for securities is subject in each case to the determination by Loomis
Sayles that the securities to be exchanged are acceptable for purchase by the
Fund. Securities accepted by Loomis Sayles in exchange for Fund shares will be
valued in the same manner as the Fund's assets, as described below, as of the
time of the Fund's next determination of net asset value after such acceptance.
All dividends and subscription or other rights which are reflected in the market
price of accepted securities at the time of valuation become the property of the
Fund and must be delivered to the Fund upon receipt by the investor from the
issuer. A gain or loss for federal income tax purposes would be realized upon
the exchange by an investor that is subject to federal income taxation,
depending upon the investor's basis in the securities tendered. A shareholder
who wishes to purchase shares by exchanging securities should obtain
instructions by calling (617) 482-2450.

-12-
<PAGE>

Act or otherwise; and (3) the securities are eligible to be acquired under the
Fund's investment policies and restrictions. No investor owning 5% or more of
the Fund's shares may purchase additional Fund shares by the exchange of
securities.

Upon acceptance of your order, the Trust opens an account for you, applies
the payment to the purchase of full and fractional Fund shares and mails a
statement of the account confirming the transaction. After an account has been
established, you may send subsequent investments at any time.

The Trust reserves the right to reject any purchase order for any reason
which the Trust in its sole discretion deems appropriate. Although the Trust
does not anticipate that it will do so, the Trust reserves the right to suspend
or change the terms of the offering of its shares.

The price you pay will be the per share net asset value next calculated
after a proper investment order is received by the Trust. Shares of the Fund
are sold without any sales charge. The net asset value of the Fund's shares is
calculated by dividing the Fund's net assets by the number of shares
outstanding. Net asset value is calculated at least weekly and as of the close
of the New York Stock Exchange (the "Exchange") on each day on which an order
for purchase or redemption of Fund shares is received and on which the Exchange
is open for unrestricted trading. Portfolio securities are valued at their
market value as more fully described in the Statement of Additional Information.

HOW TO REDEEM SHARES

You can redeem your shares by sending a written request to the Trust.

Proceeds resulting from a written redemption request will normally be
mailed to you within seven days after receipt of your request in good order. If
you purchased your shares by check and your check was deposited less than
fifteen days prior to the redemption request, the Trust may withhold redemption
proceeds until your check has cleared.

Redemption proceeds may be made in money or in kind, or partly in money and
partly in kind, as determined by the Trust.

The Fund may suspend the right of redemption and may postpone payment for
more than seven days when the Exchange is closed for other than weekends or
holidays, or if permitted by the rules of the SEC when trading on the Exchange
is restricted or during an emergency which makes it impracticable for the Fund
to dispose of its securities or to determine fairly the value of its net assets,
or during any other period permitted by the SEC for the protection of investors.

OTHER INFORMATION

The Trustees may, without shareholder approval, divide the Trust's shares
of beneficial interest into multiple series. The Trust is currently divided
into seven series, including the Fund and the other funds listed on the cover of
this Prospectus.

The Fund's investment performance may from time to time be included in
advertisements about the Fund.

-13-
<PAGE>

The Fund's yield will be computed by dividing the Fund's net investment
income for a recent 30-day period by the maximum offering price (reduced by any
undeclared earned income expected to be paid shortly as a dividend) on the last
trading day of that period.

Total return for the Fund is measured by comparing the value of an
investment in the Fund at the beginning of the relevant period to the redemption
value of the investment in the Fund at the end of the period (assuming immediate
reinvestment of any dividends or capital gain distributions).

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES

Because the Fund is designed primarily for tax-exempt investors such as
pension plans, endowments and foundations, the Fund is not managed with a view
to reducing taxes. The Fund pays any net investment income to shareholders as
dividends annually in December. The Fund also distributes all of its net
realized capital gains after applying any capital loss carryovers. Any capital
gain distributions are normally made annually in December, but may, to the
extent permitted by law, be made more frequently as deemed advisable by the
Trustees. The Trustees may change the frequency with which the Fund declares or
pays dividends.

The Fund intends to qualify as a "regulated investment company" under the
Internal Revenue Code of 1986, as amended. As such, so long as the Fund
distributes substantially all its net investment income and net realized capital
gains to its shareholders on a current basis, the Fund itself does not pay any
federal income or excise tax. The Fund intends to make sufficient distributions
to be relieved of federal taxes.

Income dividends and short-term capital gain distributions are treated as
ordinary income to you whether distributed in cash or additional shares.
Distributions designated by the Fund as deriving from net gains on securities
held for more than one year but not more than 18 months and from net gains on
securities held for more than 18 months will be taxable as such whether
distributed in cash or additional shares and regardless of how long you have
held your shares. However, any loss recognized by you on the taxable
disposition of shares held for six months or less will be treated as a long-term
capital loss to the extent of any capital gain distribution you received with
respect to the shares.

In January of each year, the Trust will send you a statement showing the
federal tax status of dividends and distributions paid to you during the
preceding year.

-14-
<PAGE>

The foregoing summarizes certain U.S. federal income tax consequences of
investing in the Fund. Before investing, you should consult your own tax
adviser for more information concerning the federal, foreign, state and local
tax consequences of investing in, redeeming or exchanging Fund shares.

15
<PAGE>

APPENDIX A

DESCRIPTION OF BOND RATINGS ASSIGNED BY
STANDARD & POOR'S AND
MOODY'S INVESTORS SERVICE, INC.

STANDARD & POOR'S
- -----------------

AAA

This is the highest rating assigned by Standard & Poor's to a debt obligation
and indicates an extremely strong capacity to pay interest and repay principal.

BBB

BB, B, CCC, CC

The rating C is reserved for income bonds on which no interest is being paid.

Bonds rated D are in default, and payment of interest and/or repayment of
principal is in arrears.

This symbol is attached to the ratings of instruments with significant noncredit
risks such as risks to principal or volatility of expected returns.

Plus (+) or Minus (-): The ratings from "AA" to "B" may be modified by the
addition of a plus or minus sign to show relative standing within the major
rating categories.

A-1
<PAGE>

MOODY'S INVESTORS SERVICE, INC.
- -------------------------------

AAA

BAA

CAA

Bonds which are rated Caa are of poor standing. Such issues may be in default
or there may be present elements of danger with respect to principal or
interest.

Bonds which are rated Ca represent obligations which are speculative in a high
degree. Such issues are often in default or have other marked shortcomings.

A-2
<PAGE>

Bonds which are rated C are the lowest rated class of bonds, and issues so rated
can be regarded as having extremely poor prospects of ever attaining any real
investment standing.

Should no rating be assigned by Moody's, the reason may be one of the following:

1. An application for rating was not received or accepted.

2. The issue or issuer belongs to a group of securities that are not rated
as a matter of policy.

3. There is lack of essential data pertaining to the issue or issuer.

4. The issue was privately placed in which case the rating is not
published in Moody's publications.

s:\lsit\prosp&sa\1998\fipro.wpd

A-3
<PAGE>

LOOMIS SAYLES INVESTMENT TRUST
LOOMIS SAYLES HIGH YIELD FIXED INCOME FUND
ONE FINANCIAL CENTER
BOSTON, MASSACHUSETTS 02111
(617) 482-2450

PROSPECTUS
APRIL 22, 1998

The Loomis Sayles Investment Trust (the "Trust") is a group of seven mutual
funds including the Loomis Sayles High Yield Fixed Income Fund (the "Fund"). The
other series, which are described in separate prospectuses, are:

Loomis Sayles California Tax-Free Income Fund
Loomis Sayles Core Fixed Income Fund
Loomis Sayles Core Growth Fund
Loomis Sayles Fixed Income Fund
Loomis Sayles Intermediate Duration Fixed Income Fund
Loomis Sayles Investment Grade Fixed Income Fund

This Prospectus concisely describes the information that you should know
before investing in the Fund. Please read it carefully and keep it for future
reference. A Statement of Additional Information dated April 22, 1998 is
available free of charge; to obtain a free copy or to make any inquiries about
the Fund, write to Loomis Sayles Investment Trust, One Financial Center, Boston,
Massachusetts 02111 or telephone (617) 482-2450. The Statement of Additional
Information, which contains more detailed information about the Fund, has been
filed with the Securities and Exchange Commission (the "SEC") and is
incorporated by reference into this Prospectus.

THE LOOMIS SAYLES HIGH YIELD FIXED INCOME FUND WILL NORMALLY INVEST AT
LEAST 65% OF ITS ASSETS IN LOWER RATED FIXED INCOME SECURITIES, COMMONLY KNOWN
AS "JUNK BONDS" AND MAY INVEST WITHOUT LIMIT IN SUCH SECURITIES. INVESTMENTS OF
THIS TYPE ARE SUBJECT TO A GREATER RISK OF LOSS OF PRINCIPAL AND NON-PAYMENT OF
INTEREST. INVESTORS SHOULD ASSESS CAREFULLY THE RISKS ASSOCIATED WITH AN
INVESTMENT IN THE LOOMIS SAYLES HIGH YIELD FIXED INCOME FUND. SEE "MORE
INFORMATION ABOUT THE FUND'S INVESTMENTS; LOWER RATED FIXED INCOME SECURITIES."
<PAGE>

TABLE OF CONTENTS

<TABLE>
<S> <C>
SUMMARY OF EXPENSES............................................ -3-

FINANCIAL HIGHLIGHTS........................................... -4-

PRIOR PERFORMANCE.............................................. -5-

THE TRUST...................................................... -6-

INVESTMENT OBJECTIVE AND POLICIES.............................. -6-

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS.................. -7-

THE FUND'S INVESTMENT ADVISER..................................-11-

FUND EXPENSES..................................................-12-

PORTFOLIO TRANSACTIONS.........................................-12-

HOW TO PURCHASE SHARES.........................................-12-

HOW TO REDEEM SHARES...........................................-13-

OTHER INFORMATION..............................................-13-

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES................-14-

[APPENDIX A -A-1-]
</TABLE>

-2-
<PAGE>

SUMMARY OF EXPENSES

Annual Fund Operating Expenses
(as a percentage of average net assets):
Management Fees (after expense
limitation) .60%
12b-1 Fees none
Other Operating Expenses (after expense
limitation)/1/ .15%
Total Fund Operating Expenses (after expense
limitation)/1/ .75%

Example
You would pay the following
expenses on a $1,000 investment
assuming a 5% annual return
(with or without a redemption at
the end of each time period):

One Year $8
Three Years $24
Five Years $42
Ten Years $93

______________________________

/1/ Loomis Sayles has voluntarily undertaken for an indefinite period to limit
the Fund's total Fund operating expenses to the percentage of average net assets
shown above. In the absence of the voluntary expense limitation, Other
Operating Expenses and Total Fund Operating Expenses for the fiscal year ended
December 31, 1997 would have been 0.57% and 1.17%, respectively.

-3-
<PAGE>

FINANCIAL HIGHLIGHTS

The financial highlights table that follows is for the period March 7,
1997 through December 31, 1997. The following information should be read in
conjunction with the financial highlights, financial statements, and notes
thereto that have been audited by Coopers & Lybrand, L.L.P., independent
accountants, whose report thereon appears in the Fund's 1997 Annual Report,
which is incorporated by reference into this Prospectus and the Statement of
Additional Information.

March 7+ through
December 31, 1997

<TABLE>
<CAPTION>
- ------------------------------------------------------------------------
<S> <C>
Net asset value, beginning of period......................... $ 10.09

Income from investment operations -
Net investment income....................................... 0.62
Net realized and unrealized gain (loss) on investments...... 0.35
-------
Total from investment operations........................... 0.97

Less distributions -
Dividends from net investment income........................ (0.71)
Distributions from net realized capital gains............... (0.31)
-------
Total distributions........................................ (1.02)
-------
Net asset value, end of period............................... $ 10.04
=======

Total return (%)............................................. 9.6**
Net assets, end of period (000).............................. $28,872
Ratio of operating expenses to average net assets (%)........ 0.75*
Ratio of net investment income to average net assets (%)..... 8.77*
Portfolio turnover rate (%).................................. 64.4**
Without giving effect to the voluntary expense limitations:
The ratio of operating expenses to average net assets
would have been (%)....................................... 1.15*
The net investment income per share would have been......... $ 0.60
</TABLE>

+Date of effectiveness of the Fund's registration statement under the Securities
Act of 1933, as amended.
*Annualized.
**Not annualized.

-4-
<PAGE>

PRIOR PERFORMANCE

(FOR A SHARE OF THE FUND OUTSTANDING THROUGHOUT THE INDICATED PERIODS)

The information presented below, for the periods indicated, relates to
periods prior to the effectiveness of the Fund's registration statement under
the Securities Act of 1933, as amended (the "1933 Act"). The following
information should be read in conjunction with the financial highlights,
financial statements, and notes thereto that have been audited by Coopers &
Lybrand, L.L.P., independent accountants, whose report thereon appears in the
Fund's 1997 Annual Report, which is incorporated by reference into this
Prospectus and the Statement of Additional Information. The Fund is managed in a
manner that is in all material respects similar to the manner in which it was
managed prior to the effectiveness of its registration statement under the 1933
Act.

<TABLE>
<CAPTION>
January 1, June 5* through
1997 through December 31,
March 6, 1997 1996
-------------- ----------------
<S> <C> <C>
Net asset value, beginning of period......................... $ 10.16 $ 10.00

Income from investment operations -
Net investment income....................................... 0.08 0.56
Net realized and unrealized gain (loss) on investments...... (0.15) 0.21
--------- -------
Total from investment operations........................... (0.07) 0.77

Less distributions -
Dividends from net investment income........................ 0.00 (0.56)
Distributions from net realized capital gains............... 0.00 (0.05)
--------- -------
Total distributions........................................ 0.00 (0.61)
--------- -------

Net asset value, end of period............................... $ 10.09 $ 10.16
========= =======

Total return (%)............................................. (0.7)*** 7.7***
Net assets, end of period (000).............................. $ 12,904 $ 3,100
Ratio of operating expenses to average net assets (%)........ 0.75** 0.75**
Ratio of net investment income to average net assets (%)..... 8.84** 9.42**
Portfolio turnover rate (%).................................. 49.4*** 9.1***
Without giving effect to the voluntary expense limitations:
The ratio of operating expenses to average net assets
would have been (%)....................................... 1.48** 2.73**
The net investment income per share would have been ........ $ 0.07 $ 0.44
</TABLE>

* Commencement of operations.
**Annualized.
***Not annualized.

-5-
<PAGE>

THE TRUST

The Fund is a series of the Trust. The Trust is a diversified open-end
management investment company which was organized as a Massachusetts business
trust on December 23, 1993. The Trust is authorized to issue an unlimited number
of full and fractional shares of beneficial interest in multiple series. Shares
are freely transferable and entitle shareholders to receive dividends as
determined by the Trust's board of trustees (the "Trustees") and to cast a vote
for each share held (with a fractional vote for each fractional share held) at
shareholder meetings. The Trust does not generally hold shareholder meetings and
will do so only when required by law. Shareholders may call meetings to consider
removal of the Trustees.

INVESTMENT OBJECTIVE AND POLICIES

The Fund's investment objective is high total investment return
through a combination of current income and capital appreciation.

The Fund seeks to attain its objective by normally investing
substantially all of its assets in a broad range of debt securities, although up
to 20% of its assets may be invested in preferred stocks and up to 10% in common
stocks. Debt securities may include corporate securities, securities issued or
guaranteed by the U.S. Government, its authorities, agencies or
instrumentalities and certificates representing undivided interests in the
interest or principal of U.S. Treasury securities ("U.S. Government
Securities"), zero coupon securities, collateralized mortgage securities,
including interest-only and principal-only ("IOs" and POs") classes of mortgage-
backed securities, convertible bonds and when-issued securities, which are
described herein (together with their related risks) under "More Information
About the Fund's Investments." The Fund may invest any portion of its assets in
securities of Canadian issuers, and a limited portion of its assets in
securities of other foreign issuers. See "More Information About the Fund's
Investments; Foreign Securities."

The Fund normally will invest at least 65% of its total assets in
fixed income securities that are of below investment grade quality at the time
of purchase, which are securities rated below BBB by Standard & Poor's ("S&P")
or below Baa by Moody's Investors Service, Inc. ("Moody's"), or unrated
securities determined by Loomis Sayles to be of comparable quality. Securities
of below investment grade are commonly referred to as "junk bonds." The Fund
may continue to hold securities that are downgraded in quality subsequent to
their purchase if, in the opinion of Loomis Sayles, it would be advantageous to
do so. See "More Information About the Fund's Investments; Lower Rated Fixed
Income Securities" below.

The percentages of the Fund's net assets invested during the fiscal
year ended December 31, 1997 in securities assigned to the various rating
categories by S&P and Moody's on a dollar-weighted basis were approximately as
follows: "AAA"/"Aaa," 0.3%; "AA"/"Aa," 0%; "A"/"A," 0%; "BBB"/"Baa," 7.5%;
"BB"/"Ba," 51.9%; "B"/"B," 40.3%; and below "B" 0%. The percentage of the
Fund's net assets invested during such fiscal year in unrated debt securities as
a group was approximately 4.52%. The percentages of the Fund's net assets
invested during such fiscal year in such unrated securities (categorized by
comparable rating category) were approximately as follows: "AAA"/"Aaa," 0%;
"AA"/"Aa," 0%; "A"/"A," 0%; "BBB"/"Baa," 0%; "BB"/"Ba," 4.52%; "B"/"B," 0%; and
below "B," 0%.

Some of the Fund's investment restrictions are "fundamental" and
cannot be changed without a majority vote of the Fund's shareholders. Such
restrictions include: (1) a restriction prohibiting the Fund from making loans;
(2) a restriction prohibiting the Fund from purchasing a security (other than
U.S. Government Securities) if, as a result, more than 25% of the Fund's total
assets (taken at current value) would be invested in any one industry; (3) a
restriction prohibiting the Fund from borrowing money in excess of 10% of its
total assets (taken at cost) or 5% of its total assets (taken at current value),
whichever is lower, and from borrowing any money except as a temporary measure
for extraordinary or emergency purposes; and (4) a restriction prohibiting the
Fund from purchasing any illiquid security including a security that is not
readily marketable if, as a result, more than 15% of the Fund's net assets based
on current value would then be invested in such security. For additional
investment restrictions, see the Statement of Additional Information.

-6-
<PAGE>

The investment objective of the Fund is "fundamental" and cannot be
changed without a majority vote of the Fund's shareholders. All investment
policies other than those that are identified as "fundamental" may be changed by
the Trustees without a vote of the Fund's shareholders.

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS

The net asset value of the Fund's shares will vary as a result of
changes in the value of securities in the Fund's portfolio. The following
describes the types of securities in which the Fund will principally invest and
the risks associated with them. Additional information about the Fund's
investment practices can be found in the Statement of Additional Information.

FIXED INCOME SECURITIES
- -----------------------

The Fund may invest in fixed income securities of any maturity. Fixed
income securities pay a specified rate of interest or dividends. Fixed income
securities include securities issued by federal, state, local and foreign
governments and related agencies, and by a wide range of foreign and domestic
private issuers. The Fund may also invest in other debt securities that pay a
rate of interest or dividends that is adjusted periodically by reference to some
specified index or market rate. Such securities are included within the
definition of fixed income securities as used in this Prospectus other than for
purposes of determining compliance with the Fund's investment policy of
investing, under normal market conditions, at least 65% of its total assets in
fixed income securities of below investment grade quality. Because interest
rates vary, it is impossible to predict the income of the Fund for any
particular period.

Fixed income securities are subject to market and credit risk. Market
risk relates to changes in a security's value as a result of changes in interest
rates generally. In general, the values of fixed income securities increase
when prevailing interest rates fall and decrease when interest rates rise.
Credit risk relates to the ability of the issuer to make payments of principal
and interest. Generally, the longer the maturity of a fixed income security,
the greater the fluctuations in its value because of market and credit risk.

LOWER RATED FIXED INCOME SECURITIES
- -----------------------------------

The Fund will normally invest at least 65% of its assets in securities
rated below investment grade ("lower rated fixed income securities"), including
securities in the lowest rating categories, and unrated securities determined by
Loomis Sayles to be of comparable quality. Lower rated fixed income securities
generally provide higher yields, but are subject to greater credit and market
risk than higher quality fixed income securities. Lower rated fixed income
securities are considered speculative with respect to the ability of the issuer
to meet principal and interest payments. Achievement of the Fund's investment
objective through investments in lower rated fixed income securities may be more
dependent on Loomis Sayles's credit analysis than is the case with higher
quality bonds. The market for lower rated fixed income securities may be more
severely affected than other financial markets by economic recession or
substantial interest rate increases. The value and liquidity of lower rated
fixed income securities may be diminished by adverse publicity and investor
perceptions. In addition, legislation that limits the tax benefits to issuers
or holders of taxable lower rated fixed income securities or that limits the
ability of certain categories of financial institutions to invest in these
securities may adversely affect their market value. The secondary market for
lower rated fixed income securities may be less liquid than the secondary market
for higher rated fixed income securities. This lack of liquidity at certain
times may affect the values of these securities and may make the valuation and
sale of these securities by the Fund more difficult. Securities of below
investment grade quality are commonly referred to as "junk bonds." Certain
lower rated fixed income securities do not pay interest on a current basis.
However, the Fund will accrue and distribute this interest

-7-
<PAGE>

on a current basis, and may be required to sell securities at times when Loomis
Sayles would not otherwise deem it desirable to do so in order to generate cash
for distributions. Securities in the lowest rating categories may be in poor
standing or in default. Investment grade fixed income securities (rated BBB by
S&P or Baa by Moody's) may share some of the characteristics of lower rated
fixed income securities described above.

U.S. GOVERNMENT SECURITIES
- --------------------------

U.S. Government Securities have different kinds of government support.
For example, some U.S. Government Securities, such as U.S. Treasury bonds, are
supported by the full faith and credit of the United States, whereas certain
other U.S. Government Securities issued or guaranteed by federal agencies or
government-sponsored enterprises are not supported by the full faith and credit
of the United States.

Although U.S. Government Securities generally do not involve the
credit risks associated with other types of fixed income securities, the market
values of U.S. Government Securities will fluctuate as interest rates change.
Thus, for example, the value of an investment in U.S. Government Securities may
fall during times of rising interest rates. Yields on U.S. Government
Securities tend to be lower than those of other fixed income securities of
comparable maturities.

Some U.S. Government Securities, such as Government National Mortgage
Association Certificates, are known as "mortgage-backed" securities,
representing interests in "pools" of mortgage loans secured by residential or
commercial real property. Interest and principal payments on the mortgages
underlying mortgage-backed U.S. Government Securities are passed through to the
holders of the security. If the Fund purchases mortgage-backed securities at a
discount or a premium, the Fund will recognize a gain or loss when the payments
of principal, through prepayment or otherwise, are passed through to the Fund
and, if the payment occurs in a period of falling interest rates, the Fund may
not be able to reinvest the payment at as favorable an interest rate. As a
result of these principal prepayment features, mortgage-backed securities are
generally more volatile investments than many other fixed income securities.
See "Collateralized Mortgage Obligations" below for additional information
regarding the risks associated with mortgage-backed securities.

In addition to investing directly in U.S. Government Securities, the
Fund may purchase certificates of accrual or similar instruments ("strips")
evidencing undivided ownership interests in interest payments or principal
payments, or both, in U.S. Treasury securities. These investment instruments
may be highly volatile.

ZERO COUPON SECURITIES
- ----------------------

COLLATERALIZED MORTGAGE OBLIGATIONS
- -----------------------------------

-8-
<PAGE>

securities. As with other mortgage-backed securities, the early retirement of a
particular class or series of CMOs held by the Fund could involve the loss of
any premium the Fund paid when it acquired the investment and could result in
the Fund's reinvesting the proceeds at a lower interest rate than the interest
rate paid by the retired CMO. Because of the early retirement feature, CMOs may
be more volatile than many other fixed income investments. In addition, slower
than anticipated prepayments on the underlying mortgages can extend the
effective maturities of CMOs, subjecting them to a greater risk of decline in
market value in response to rising interest rates than traditional debt
securities.

COMMERCIAL MORTGAGE-BACKED SECURITIES
- -------------------------------------

The Fund may invest in commercial mortgage-backed securities.
Commercial mortgage-backed securities are securities that represent an interest
in, or are secured by, mortgage loans secured by commercial property, such as
industrial and warehouse properties, office buildings, retail space and shopping
malls, multifamily properties and cooperative apartments, hotels and motels,
nursing homes, hospitals, and senior living centers. The commercial mortgage-
backed securities market is newer and in terms of total outstanding principal
amount of issues is relatively small compared to the total size of the market
for residential mortgage-backed securities.

Commercial mortgage-backed securities are generally structured
similarly to pass-through securities or to CMOs, although other structures are
possible. They may pay fixed or adjustable rates of interest. Commercial
mortgage-backed securities have been issued in public or private transactions by
a variety of public and private issuers.

The commercial mortgage loans that underlie commercial mortgage-backed
securities have certain distinct risk characteristics. Commercial mortgage
loans generally lack standardized terms, which may complicate their structure.
Commercial properties themselves tend to be unique and are more difficult to
value than single-family residential properties. Commercial mortgage loans also
tend to have shorter maturities than residential mortgage loans, and may not be
fully amortizing, meaning that they have a significant principal balance, or
"balloon" payment, due on maturity. Assets underlying commercial mortgage-backed
securities may relate only to a few properties or a single property. The risk
involved in single property financings is highly concentrated. In addition,
commercial properties, particularly industrial and warehouse properties, are
subject to environmental risks and the burdens and costs of compliance with
environmental laws and regulations. At the same time, commercial mortgage-
backed securities may have a lower prepayment risk than residential mortgage-
backed securities, because commercial mortgage loans generally prohibit or
impose penalties on prepayments of principal. In addition, commercial mortgage-
backed securities often are structured with some form of credit enhancement to
protect against potential losses on the underlying mortgage loans.

STRIPPED MORTGAGE-BACKED SECURITIES
- -----------------------------------

The Fund may invest in interest-only and principal-only ("IOs" and
"POs") classes of mortgage-backed securities. The yield to maturity on an IO or
PO class of stripped mortgage-backed securities is extremely sensitive not only
to changes in prevailing interest rates but also to the rate of principal
payments (including prepayments) on the underlying assets. A rapid rate of
principal prepayments may have a measurably adverse effect on the fund's yield
to maturity to the extent it invests in IOs. If the assets underlying the IOs
experience greater than anticipated prepayments of principal, the fund may fail
to recoup fully its initial investment in these securities. Conversely, POs
tend to increase in value if prepayments are greater than anticipated and
decline if prepayments are slower than anticipated.

WHEN-ISSUED SECURITIES
- ----------------------

-9-
<PAGE>

15 to 120 days later. No interest accrues on the security between the time the
Fund enters into the commitment and the time the security is issued. If the
value of the security being purchased falls between the time the Fund commits to
buy it and the payment date, the Fund may sustain a loss. The risk of this loss
is in addition to the Fund's risk of loss on the securities actually in its
portfolio at the time. When the Fund buys a security on a when-issued basis, it
is subject to the risk that market rates of interest will increase before the
time the security is delivered, with the result that the yield on the security
delivered to the Fund may be lower than the yield available on other, comparable
securities at the time of delivery. If the Fund has outstanding obligations to
buy when-issued securities, it will maintain liquid assets in a segregated
account at its custodian bank in an amount sufficient to satisfy these
obligations.

FOREIGN SECURITIES
- ------------------

The Fund may invest in securities principally traded in foreign
markets ("foreign securities"). The Fund will not purchase a foreign security
if, as a result, the Fund's total holdings of foreign securities would exceed
50% of the Fund's total assets.

Foreign securities may present risks not associated with investments
in comparable securities of U.S. issuers. There may be less information
publicly available about a foreign corporate or governmental issuer than about a
U.S. issuer, and foreign issuers are not generally subject to accounting,
auditing and financial reporting standards and practices comparable to those in
the United States. The securities of some foreign issuers are less liquid and
at times more volatile than securities of comparable U.S. issuers. Foreign
brokerage commissions and securities custody costs are often higher than in the
United States. With respect to certain foreign countries, there is a
possibility of governmental expropriation of assets, confiscatory taxation,
political or financial instability and diplomatic developments that could affect
the value of investments in those countries. The Fund's receipt of interest on
foreign government securities may depend on the availability of tax or other
revenues to satisfy the issuer's obligations. In addition, the remedies of the
Fund may be extremely limited if a foreign issuer defaults on its obligations.

The Fund's investments in foreign securities may include investments
in countries whose economies or securities markets are not yet highly developed.
Special considerations associated with these investments (in addition to
considerations regarding foreign investments generally) may include, among
others, greater political uncertainties, an economy's dependence on revenues
from particular commodities or on international aid or development assistance,
currency transfer restrictions, highly limited numbers of potential buyers for
such securities and delays and disruptions in securities settlement procedures.

Since most foreign securities are denominated in foreign currencies or
traded primarily in securities markets in which settlements are made in foreign
currencies, the value of these investments and the net investment income
available for distribution to shareholders of the Fund may be affected favorably
or unfavorably by changes in currency exchange rates, exchange control
regulations, or foreign withholding. Changes in the value relative to the U.S.
dollar of a foreign currency in which the Fund's holdings are denominated will
result in a change in the U.S. dollar value of the Fund's assets and the Fund's
income available for distribution.

In addition, although part of the Fund's income may be received or
realized in foreign currencies, the Fund will be required to compute and
distribute its income in U.S. dollars. Therefore, if the value of a currency
relative to the U.S. dollar declines after the Fund's income has been earned in
that currency, translated into U.S. dollars and declared as a dividend, but
before payment of the dividend, the Fund could be required to liquidate
portfolio securities to pay the dividend. Similarly, if the value of a currency
relative to the U.S. dollar declines between the time the Fund accrues expenses
in U.S. dollars and the time such expenses are paid, the amount of such currency
required to be converted into U.S. dollars will be greater than the equivalent
amount in such currency of such expenses at the time they were incurred.

CONVERTIBLE SECURITIES
- ----------------------

-10-
<PAGE>

securities also include other securities, such as warrants, that provide an
opportunity for equity participation. Because convertible securities can be
converted into equity securities, their value will normally vary in some
proportion with those of the underlying equity securities. Convertible
securities usually provide a higher yield than the underlying equity security,
however, so that when the price of the underlying equity security falls, the
decline in the price of the convertible security may sometimes be less
substantial than that of the underlying equity security. Due to the conversion
feature, convertible securities generally yield less than nonconvertible fixed
income securities of similar credit quality and maturity. The Fund's investment
in convertible securities may at times include securities that have a mandatory
conversion feature, pursuant to which the securities convert automatically into
common stock at a specified date and conversion ratio, or that are convertible
at the option of the issuer. Because conversion is not at the option of the
holder, the Fund may be required to convert the security into the underlying
common stock even at times when the value of the underlying common stock has
declined substantially.

COMMON STOCKS
- -------------

The Fund may invest up to 10% of its total assets in common stocks,
usually as a result of warrants associated with debt instruments purchased by
the Fund, but also under certain circumstances to seek capital appreciation.
Common stocks, like other equity securities, offer greater potential for long-
term growth but are more risky than some other forms of investment.

YEAR 2000
- ---------

Many computer software systems in use today cannot properly process
date-related information from and after January 1, 2000. Should any of the
computer systems employed by the Fund's major service providers fail to process
this type of information properly, that could have a negative impact on the
Fund's operations and the services that are provided to the Fund's shareholders.
Loomis Sayles has advised the Fund that it is reviewing all of its computer
systems with the goal of modifying or replacing such systems prior to January 1,
2000, to the extent necessary to foreclose any such negative impact. In
addition, Loomis Sayles has been advised by the Fund's custodian that it is also
in the process of reviewing its systems with the same goal. As of the date of
this prospectus, the Fund and Loomis Sayles have no reason to believe that these
goals will not be achieved. Similarly, the values of certain of the portfolio
-------------------------------------------------
securities held by the Fund may be adversely affected by the inability of the
- -----------------------------------------------------------------------------
securities' issuers or of third parties to process this type of information
- ---------------------------------------------------------------------------
properly.
- ---------

THE FUND'S INVESTMENT ADVISER

The Fund's investment adviser is Loomis Sayles, One Financial Center,
Boston, Massachusetts 02111. Founded in 1926, Loomis Sayles is one of the
country's oldest and largest investment firms.

The general partner of Loomis Sayles is a special purpose corporation
that is an indirect wholly-owned subsidiary of Nvest Companies, L.P. ("Nvest
Companies"). Nvest Companies' managing general partner, Nvest Corporation, is a
direct wholly-owned subsidiary of Metropolitan Life Insurance Company ("Met
Life"), a mutual life insurance company. Nvest Companies' advising general
partner, Nvest, L.P., is a publicly traded company listed on the New York Stock
Exchange. Nvest Corporation is the sole general partner of Nvest L.P.

In addition to selecting and reviewing the Fund's investments, Loomis
Sayles provides executive and other personnel for the management of the Fund.
The Board of Trustees supervises Loomis Sayles's conduct of the affairs of the
Fund.

-11-
<PAGE>

The portfolio manager for the Fund since its inception has been Daniel
J. Fuss, who has been with Loomis Sayles since 1976 and is head of the Fixed
Income Management Group. Mr. Fuss is an Executive Vice President and Director
of Loomis Sayles.

FUND EXPENSES

The Fund pays Loomis Sayles a monthly investment advisory fee. This
fee is paid at the annual rate of .60% of the Fund's average daily net
assets.

In addition to the investment advisory fee, the Fund pays all expenses
not expressly assumed by Loomis Sayles, including taxes, brokerage commissions,
fees of the Fund's custodian, independent accountants and legal counsel and fees
of the Trustees who are not directors, officers or employees of Loomis Sayles or
its affiliated companies.

Loomis Sayles has voluntarily undertaken for an indefinite period to
waive its fees and, to the extent necessary, to bear other Fund expenses in
order to limit the Fund's annualized total operating expenses to .75% of average
annual net assets.

PORTFOLIO TRANSACTIONS

Loomis Sayles selects brokers and dealers to execute portfolio
transactions for the Fund. Portfolio turnover considerations will not limit
Loomis Sayles's investment discretion in managing the Fund's assets. The Fund
anticipates that its portfolio turnover rates will vary significantly from time
to time depending on the volatility of economic and market conditions. High
portfolio turnover may result in higher costs such as higher brokerage
commissions and higher levels of taxable gains. Portfolio turnover rates for
the life of the Fund are set forth above under the headings "Financial
Highlights" and "Prior Performance." See "Dividends, Capital Gain Distributions
and Taxes" for information on the tax consequences of investing in the Fund.

HOW TO PURCHASE SHARES

You may make an initial purchase of shares of the Fund by submitting a
completed application form and payment to Loomis Sayles.

The minimum initial investment in the Fund is $3,000,000. Subsequent
investments must be at least $50,000. The Trust reserves the right to waive
these minimums in its sole discretion.

Shares of the Fund may be purchased by exchange of (I) cash, (ii)
securities on deposit with a custodian acceptable to Loomis Sayles or (iii) a
combination of such securities and cash. Purchase of shares of the Fund in
exchange for securities is subject in each case to the determination by Loomis
Sayles that the securities to be exchanged are acceptable for purchase by the
Fund. Securities accepted by Loomis Sayles in exchange for Fund shares will be
valued in the same manner as the Fund's assets, as described below, as of the
time of the Fund's next determination of net asset value after such acceptance.
All dividends and subscription or other rights which are reflected in the market
price of accepted securities at the time of valuation become the property of the
Fund and must be delivered to the Fund upon receipt by the investor from the
issuer. A gain or loss for federal income tax purposes would be realized upon
the exchange by an investor that is subject to federal income taxation,
depending upon the investor's basis in the securities tendered. A shareholder
who wishes to purchase shares by exchanging securities should obtain
instructions by calling (617) 482-2450.

-12-
<PAGE>

represents and agrees that all securities offered to the Fund can be resold by
the Fund without restriction under the 1933 Act or otherwise; and (3) the
securities are eligible to be acquired under the Fund's investment policies and
restrictions. No investor owning 5% or more of the Fund's shares may purchase
additional Fund shares by exchange of securities.

Upon acceptance of your order, the Trust opens an account for you,
applies the payment to the purchase of full and fractional Fund shares and mails
a statement of the account confirming the transaction. After an account has
been established, you may send subsequent investments at any time.

The Trust reserves the right to reject any purchase order for any
reason which the Trust in its sole discretion deems appropriate. Although the
Trust does not anticipate that it will do so, the Trust reserves the right to
suspend or change the terms of the offering of its shares.

The price you pay will be the per share net asset value next
calculated after a proper investment order is received by the Trust. Shares of
the Fund are sold without any sales charge. The net asset value of the Fund's
shares is calculated by dividing the Fund's net assets by the number of shares
outstanding. Net asset value is calculated at least weekly and as of the close
of the New York Stock Exchange (the "Exchange") on each day on which an order
for purchase or redemption of Fund shares is received and on which the Exchange
is open for unrestricted trading. Portfolio securities are valued at their
market value as more fully described in the Statement of Additional Information.

HOW TO REDEEM SHARES

You can redeem your shares by sending a written request to the Trust.

The written request must include the name of the Fund, your account
number, the exact name(s) in which your shares are registered, and the number of
shares or the dollar amount to be redeemed. All owners of the shares must sign
the written request in the exact names in which the shares are registered and
should indicate any special capacity in which they are signing (such as trustee
or custodian or on behalf of a partnership, corporation or other entity).

The redemption price will be the net asset value per share next
determined after the written redemption request is received by the Trust in
proper form. The Trust usually requires additional documentation for the sale
of shares by a corporation, partnership, agent or fiduciary, or a surviving
joint owner. Contact the Trust by calling (617) 482-2450 for details.

Proceeds resulting from a written redemption request will normally be
mailed to you within seven days after receipt of your request in good order. If
you purchased your shares by check and your check was deposited less than
fifteen days prior to the redemption request, the Trust may withhold redemption
proceeds until your check has cleared.

Redemption proceeds may be made in money or in kind, or partly in
money and partly in kind, as determined by the Trust.

The Fund may suspend the right of redemption and may postpone payment
for more than seven days when the Exchange is closed for other than weekends or
holidays, or if permitted by the rules of the SEC when trading on the Exchange
is restricted or during an emergency which makes it impracticable for the Fund
to dispose of its securities or to determine fairly the value of its net assets,
or during any other period permitted by the SEC for the protection of investors.

OTHER INFORMATION

The Trustees may, without shareholder approval, divide the Trust's
shares of beneficial interest into multiple series. The Trust is currently
divided into seven series, including the Fund and the other funds listed on the
cover of this Prospectus.

-13-
<PAGE>

As of March 31, 1998, each of Trustees of Clark University and Blue
Cross Blue Shield of Massachusetts, Inc. Retirement Trust may be deemed to
control the Fund because each possessed, directly or indirectly, beneficial
ownership of more than 25% of the Fund's shares.

The Fund's investment performance may from time to time be included in
advertisements about the Fund.

The Fund's yield will be computed by dividing the Fund's net
investment income for a recent 30-day period by the maximum offering price
(reduced by any undeclared earned income expected to be paid shortly as a
dividend) on the last trading day of that period.

Total return for the Fund is measured by comparing the value of an
investment in the Fund at the beginning of the relevant period to the redemption
value of the investment in the Fund at the end of the period (assuming immediate
reinvestment of any dividends or capital gain distributions).

All data are based on the Fund's past investment results and do not
predict future performance. Investment performance, which will vary, is based
on many factors, including market conditions, the composition of the Fund's
portfolio and the Fund's operating expenses. Investment performance also often
reflects the risks associated with the Fund's investment objectives and
policies. These factors should be considered when comparing the Fund's
investment results with those of other mutual funds and other investment
vehicles. Quotations of investment performance for any period when an expense
limitation was in effect will be greater than if the limitation had not been in
effect.

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES

Because the Fund is designed primarily for tax-exempt investors such
as pension plans, endowments and foundations, the Fund is not managed with a
view to reducing taxes. The Fund pays any net investment income to shareholders
as dividends annually in December. The Fund also distributes all of its net
realized capital gains after applying any capital loss carryovers. Any capital
gain distributions are normally made annually in December, but may, to the
extent permitted by law, be made more frequently as deemed advisable by the
Trustees. The Trustees may change the frequency with which the Fund declares or
pays dividends.

The Fund intends to qualify as a "regulated investment company" under
the Internal Revenue Code of 1986, as amended. As such, so long as the Fund
distributes substantially all its net investment income and net realized capital
gains to its shareholders on a current basis, the Fund itself does not pay any
federal income or excise tax. The Fund intends to make sufficient distributions
to be relieved of federal taxes.

Income dividends and short-term capital gain distributions are treated
as ordinary income to you whether distributed in cash or additional shares.
Distributions designated by the Fund as deriving from net gains on securities
held for more than one year but not more than 18 months and from net gains on
securities held for more than 18 months will be taxable as such whether
distributed in cash or additional shares and regardless of how long you have
held your shares. However, any loss recognized by you on the taxable
disposition of shares held for six months or less will be treated as a long-term
capital loss to the extent of any capital gain distribution you received with
respect to the shares.

-14-
<PAGE>

In January of each year, the Trust will send you a statement showing
the federal tax status of dividends and distributions paid to you during the
preceding year.

The foregoing summarizes certain U.S. federal income tax consequences
of investing in the Fund. Before investing, you should consult your own tax
adviser for more information concerning the federal, foreign, state and local
tax consequences of investing in, redeeming or exchanging Fund shares.

-15-
<PAGE>

APPENDIX A

DESCRIPTION OF BOND RATINGS ASSIGNED BY
STANDARD & POOR'S AND
MOODY'S INVESTORS SERVICE, INC.

STANDARD & POOR'S
- -----------------
AAA

This is the highest rating assigned by Standard & Poor's to a debt obligation
and indicates an extremely strong capacity to pay interest and repay principal.

BBB

BB, B, CCC, CC

The rating C is reserved for income bonds on which no interest is being paid.

Bonds rated D are in default, and payment of interest and/or repayment of
principal is in arrears.

A-1
<PAGE>

This symbol is attached to the ratings of instruments with significant noncredit
risks such as risks to principal or volatility of expected returns.

Plus (+) or Minus (-): The ratings from "AA" to "B" may be modified by the
addition of a plus or minus sign to show relative standing within the major
rating categories

MOODY'S INVESTORS SERVICE, INC.
- -------------------------------

AAA

BAA

CAA

Bonds which are rated Caa are of poor standing. Such issues may be in default
or there may be present elements of danger with respect to principal or
interest.

A-2
<PAGE>

Bonds which are rated Ca represent obligations which are speculative in a high
degree. Such issues are often in default or have other marked shortcomings.

Bonds which are rated C are the lowest rated class of bonds, and issues so rated
can be regarded as having extremely poor prospects of ever attaining any real
investment standing.

Should no rating be assigned by Moody's, the reason may be one of the following:

1. An application for rating was not received or accepted.

2. The issue or issuer belongs to a group of securities that are not
rated as a matter of policy.

3. There is lack of essential data pertaining to the issue or
issuer.

4. The issue was privately placed in which case the rating is not
published in Moody's publications.

A-3
<PAGE>

LOOMIS SAYLES INVESTMENT TRUST

LOOMIS SAYLES INTERMEDIATE DURATION FIXED INCOME FUND

ONE FINANCIAL CENTER
BOSTON, MASSACHUSETTS 02111
(617) 482-2450

PROSPECTUS

APRIL 22, 1998

The Loomis Sayles Investment Trust (the "Trust") is a group of seven mutual
funds including the Loomis Sayles Intermediate Duration Fixed Income Fund (the
"Fund"). The other series, which are described in separate prospectuses, are:

Loomis Sayles California Tax-Free Income Fund
Loomis Sayles Core Fixed Income Fund
Loomis Sayles Core Growth Fund
Loomis Sayles Fixed Income Fund
Loomis Sayles High Yield Fixed Income Fund
Loomis Sayles Investment Grade Fixed Income Fund

This Prospectus concisely describes the information that you should know
before investing in the Fund. Please read it carefully and keep it for future
reference. A Statement of Additional Information dated April 22, 1998, is
available free of charge; to obtain a free copy or to make any inquiries about
the Fund write to Loomis Sayles Investment Trust, One Financial Center, Boston,
Massachusetts 02111 or telephone (617) 482-2450. The Statement of Additional
Information, which contains more detailed information about the Fund, has been
filed with the Securities and Exchange Commission (the "SEC") and is
incorporated by reference into this Prospectus.

TABLE OF CONTENTS

<TABLE>
<S> <C>
SUMMARY OF EXPENSES ...................................................... -3-

THE TRUST ................................................................ -4-

INVESTMENT OBJECTIVE AND POLICIES ........................................ -4-

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS ............................ -5-

THE FUND'S INVESTMENT ADVISER ............................................ -9-

FUND EXPENSES ............................................................ -9-

PORTFOLIO TRANSACTIONS ................................................... -9-

HOW TO PURCHASE SHARES ................................................... -9-

HOW TO REDEEM SHARES ..................................................... -10-

OTHER INFORMATION ........................................................ -11-

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES .......................... -11-

APPENDIX A ............................................................... A-1

APPENDIX B ............................................................... B-1
</TABLE>

-2-
<PAGE>

SUMMARY OF EXPENSES

The following information is provided to assist you in understanding
the various costs and expenses that, as an investor in the Fund, you will bear
directly or indirectly. The information is based on estimated annualized
expenses for the Fund's first full fiscal year. The information below should
not be considered a representation of past or future expenses, as actual
expenses may be greater or less than those shown. Also, the assumed 5% annual
return in the example should not be considered a representation of investment
performance, as actual performance will depend upon the actual investment
results of securities held in the Fund's portfolio.

Shareholder Transaction Expenses:
Maximum Sales Load Imposed on
Purchases (as a percentage of
offering price) none
Maximum Sales Load Imposed on
Reinvested Dividends (as a percentage
of offering price) none
Deferred Sales Load (as a percentage
of original purchase price or redemption
proceeds as applicable) none
Redemption Fees (as a percentage of
amount redeemed) none
Exchange Fees none

Annual Fund Operating Expenses
(as a percentage of average net assets):
Management Fees (after
expense limitation) .40%
12b-1 Fees none
Other Operating Expenses (after
expense limitation) /1/ .15%
Total Operating Expenses (after
expense limitation) /1/ .55%

Example
You would pay the following
expenses on a $1,000 investment
assuming a 5% annual return
(with or without a redemption at
the end of each time period):

One Year $ 6
Three Years $18

______________________________

/1/ Loomis Sayles has voluntarily undertaken for an indefinite period to limit
the Fund's total operating expenses to the percentage of average net assets
shown above. In the absence of the voluntary expense limitation, estimated
Management Fees, Other Operating Expenses and Total Operating Expenses for the
Fund's first fiscal year are expected to be .40%, .72% and 1.12%, respectively.

-3-

<PAGE>

THE TRUST

The Fund is a series of the Trust. The Trust is a diversified open-end
management investment company which was organized as a Massachusetts business
trust on December 23, 1993. The Trust is authorized to issue an unlimited number
of full and fractional shares of beneficial interest in multiple series. Shares
are freely transferable and entitle shareholders to receive dividends as
determined by the Trust's board of trustees (the "Trustees") and to cast a vote
for each share held (with a fractional vote for each fractional share held) at
shareholder meetings. The Trust does not generally hold shareholder meetings and
will do so only when required by law. Shareholders may call meetings to consider
removal of the Trustees.

INVESTMENT OBJECTIVE AND POLICIES

The Fund's investment objective is above-average total return through a
combination of current income and capital appreciation. Although the Fund may
invest in fixed income securities of any maturity, the weighted average duration
of the Fund's portfolio will generally remain within a band of 2 to 5 years. The
concept of duration is described more fully below.

The Fund will seek to achieve its objective by investing in a diversified
portfolio of debt securities that may include corporate securities, securities
issued or guaranteed by the U.S. Government, its authorities, agencies or
instrumentalities and certificates representing undivided interests in the
interest or principal of U.S. Treasury securities ("U.S. Government
Securities"), "Yankee" securities (U.S. dollar-denominated debt issued by non-
U.S. entities), convertible securities and certain types of mortgage-related and
asset-backed securities (including interest-only and principal-only ("IOs" and
"POs") classes of mortgage-backed securities). Under normal market conditions,
the Fund will invest at least 65% of its total assets in fixed income securities
that have a duration of 2 to 5 years at the time of purchase. Collateralized
mortgage obligations ("CMOs") will be limited to those with CMO market risk
ratings of V-1 to V-4 from Fitch Investors Service, L.P. ("Fitch"), or CMOs
unrated by Fitch that Loomis Sayles has determined to be of comparable
volatility. All securities will be denominated in U.S. dollars.

The Fund will purchase only securities rated at least Baa3 by Moody's
Investors Service, Inc. ("Moody's") or at least BBB- by Standard & Poor's
("S&P"), or, if unrated, determined to be of comparable quality by Loomis
Sayles. Some or all of these securities may be "split-rated securities," i.e.,
securities that have received an investment grade rating from one of the
nationally recognized rating organizations but that have also received a lower
rating from the other nationally recognized rating organization. Split-rated
securities may be subject to some of the risks described below under "Lower
Rated Fixed Income Securities." In the event that the credit rating of a
security held by the Fund falls below investment grade (or, in the case of an
unrated security, Loomis Sayles determines that the quality of such security has
deteriorated below investment grade), the Fund will not be obligated to dispose
of such security and may continue to hold such security if, in the opinion of
Loomis Sayles, such investment is appropriate in the circumstances.

Some of the Fund's investment restrictions are "fundamental" and cannot be
changed without a majority vote of the Fund's shareholders. Such restrictions
include: (1) a restriction prohibiting the Fund from making loans; (2) a
restriction prohibiting the Fund from purchasing a security (other than U.S.
Government Securities) if, as a result, more than 25% of the Fund's total assets
(taken at current value) would be invested in any one industry; (3) a
restriction prohibiting the Fund from borrowing money in excess of 10% of its
total assets (taken at cost) or 5% of its total assets (taken at current value),
whichever is lower, and from borrowing any money except as a temporary measure
for extraordinary or emergency purposes; and (4) a restriction prohibiting the
Fund from purchasing any illiquid security including a security that is not
readily marketable if, as a result, more than 15% of the Fund's net assets based
on current value would then be invested in such security. For additional
investment restrictions, see the Statement of Additional Information.

-4-
<PAGE>

Duration is a measure of the expected life of a fixed income security that
was developed as a more precise alternative to the concept of "term to
maturity." Most debt obligations provide interest payments in addition to a
final payment at maturity. Some debt obligations also have call provisions.
Depending on the relative magnitude of these payments, the market values of debt
obligations may respond differently to changes in the level and structure of
interest rates. Traditionally, a debt security's "term to maturity" has been
used as a proxy for the sensitivity of the security's price to changes in
interest rates. However, term to maturity measures only the time until a debt
security provides its final payment, taking no account of the pattern of the
security's payments prior to maturity. Duration is a measure of the expected
life of a fixed income security on a present value basis. Duration takes the
length of the time intervals between the present time and the time that the
interest and principal payments are scheduled or, in the case of a callable
bond, expected to be received, and weights them by the present values of the
cash to be received at each future point in time. For any fixed income security
with interest payments occurring prior to the payment of principal, duration is
always less than maturity. As a general rule, a 1% increase or decrease in
interest rates will result in approximately a 1% decrease or increase,
respectively, in the value of a security for each year of duration. For example,
a 1% increase in interest rates will result in approximately a 5% decrease in
the value of a security having a five-year duration. There are some situations,
however, where the standard duration calculation does not properly reflect the
interest rate exposure of a security. Also, in some cases, duration cannot be
calculated with certainty because certain assumptions (including assumptions
relating to prepayment rates in the case of mortgage-backed and asset-backed
securities) have to be factored into the calculation.

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS

The net asset value of the Fund's shares will vary as a result of changes
in the value of securities in the Fund's portfolio. The following describes the
types of securities in which the Fund will principally invest and the risks
associated with them. Additional information about the Fund's investment
practices can be found in the Statement of Additional Information.

FIXED INCOME SECURITIES
- -----------------------

The Fund may invest in fixed income securities of any maturity although the
weighted average duration of its investments will generally remain within a band
of 2 to 5 years. Fixed income securities pay a specified rate of interest or
dividends. Fixed income securities include securities issued by federal, state,
local and foreign governments and related agencies, and by a wide range of
foreign and domestic private issuers. The Fund may also invest in other debt
securities that pay a rate of interest or dividends that is adjusted
periodically by reference to some specified index or market rate. Such
securities are included within the definition of fixed income securities as used
in this Prospectus other than for purposes of determining compliance with the
Fund's investment policy of investing, under normal market conditions, at least
65% of its total assets in fixed income securities with a duration of 2 to 5
years. Because interest rates vary, it is impossible to predict the income of
the Fund for any particular period.

Fixed income securities are subject to market and credit risk. Market risk
relates to changes in a security's value as a result of changes in interest
rates generally. In general, the values of fixed income securities increase
when prevailing interest rates fall and decrease when interest rates rise.
Credit risk relates to the ability of the issuer to make payments of principal
and interest. Generally, the longer the maturity of a fixed income security,
the greater the fluctuations in its value because of market and credit risk.

U.S. GOVERNMENT SECURITIES
- --------------------------

Although U.S. Government Securities generally do not involve the credit
risks associated with other types of fixed income securities, the market values
of U.S. Government Securities will fluctuate as interest rates change. Thus, for
example, the value of an investment in U.S. Government Securities may fall
during times of rising interest rates. Yields on U.S. Government Securities
tend to be lower than those of other fixed income securities of comparable
maturities.

-5-
<PAGE>

In addition to investing directly in U.S. Government Securities, the Fund
may purchase certificates of accrual or similar instruments ("strips")
evidencing undivided ownership interests in interest payments or principal
payments, or both, in U.S. Treasury securities. These investment instruments may
be highly volatile.

LOWER RATED FIXED INCOME SECURITIES
- -----------------------------------

The Fund may purchase split-rated securities, which may be subject to some
of the risks associated with securities of below investment grade quality
("lower rated fixed income securities"), also known as "junk bonds". Lower rated
fixed income securities generally provide higher yields, but are subject to
greater credit and market risk than higher quality fixed income securities.
Lower rated fixed income securities are considered speculative with respect to
the ability of the issuer to meet principal and interest payments. Achievement
of the Fund's investment objective through investments in lower rated fixed
income securities may be more dependent on Loomis Sayles's credit analysis than
is the case with higher quality bonds. The market for lower rated fixed income
securities may be more severely affected than other financial markets by
economic recession or substantial interest rate increases. The value and
liquidity of lower rated fixed income securities may be diminished by adverse
publicity and investor perceptions. In addition, legislation that limits the tax
benefits to issuers or holders of taxable lower rated fixed income securities or
that limits the ability of certain categories of financial institutions to
invest in these securities may adversely affect their market value. The
secondary market for lower rated fixed income securities may be less liquid than
the secondary market for higher rated fixed income securities. This lack of
liquidity at certain times may affect the values of these securities and may
make the valuation and sale of these securities by the Fund more difficult.
Certain lower-rated fixed income securities do not pay interest on a current
basis. However, the Fund will accrue and distribute this interest on a current
basis, and may be required to sell securities at times when Loomis Sayles would
not otherwise deem it desirable to do so in order to generate cash for
distributions. Securities in the lowest rating categories may be in poor
standing or in default. Investment grade fixed income securities rated Baa by
Moody's or BBB by S&P may share some of the characteristics of lower rated fixed
income securities described above.

ZERO COUPON SECURITIES
- ----------------------

COLLATERALIZED MORTGAGE OBLIGATIONS
- -----------------------------------

The Fund may invest in CMOs. A CMO is a limited recourse security backed by
a portfolio of mortgages or, more typically, by mortgage-backed securities held
under an indenture. CMOs may be issued either by instrumentalities of the U.S.
Government or by non-governmental entities. The issuer's obligation to make
interest and principal payments is derived from and secured by the underlying
portfolio of mortgages or mortgage-backed securities. CMOs are issued with a
number of classes or series which have different maturities and which may
represent interests in some or all of the interest or principal payments on the
underlying collateral or a combination thereof. CMOs of different classes or
series are generally retired in sequence as the underlying mortgage loans in the
mortgage pool are repaid. In the event of sufficient early prepayments on such
mortgages, the class or series of CMOs first to mature generally will be retired
prior to its maturity. As with other mortgage-backed securities, the early
retirement of a particular class or series of CMOs held by the Fund could
involve the loss of any premium the Fund paid when it acquired the investment
and could result in the Fund's reinvesting the proceeds at a lower interest rate
than the interest rate paid by the retired CMO. Because of the early retirement
feature,

-6-
<PAGE>

CMOs may be more volatile than many other fixed income investments. The Fund
will invest only in CMOs with Fitch ratings of V-4 or better, or those CMOs
unrated by Fitch that Loomis Sayles has determined to be of comparable
volatility. Even CMOs with ratings reflecting the lowest market risk are likely
to experience losses in the event of adverse changes in market conditions. The
duration of CMOs and other mortgage-related securities is often difficult to
determine because the underlying mortgages may be subject to early repayment.
Thus, the determination of duration will be dependent on the adviser's
assumptions regarding the likelihood and incidence of prepayment and, to the
extent that such assumptions prove to be incorrect, the duration of the Fund's
portfolio, and thus its relative exposure to fluctuation of interest rates, may
be significantly different than intended and may increase the overall risk of
the Fund's portfolio.

COMMERCIAL MORTGAGE-BACKED SECURITIES
- -------------------------------------

Commercial mortgage-backed securities are generally structured similarly to
pass-through securities or to CMOs, although other structures are possible.
They may pay fixed or adjustable rates of interest. Commercial mortgage-backed
securities have been issued in public or private transactions by a variety of
public and private issuers.

STRIPPED MORTGAGE-BACKED SECURITIES
- -----------------------------------

WHEN-ISSUED SECURITIES
- ----------------------

-7-
<PAGE>

in its portfolio at the time. When the Fund buys a security on a when-issued
basis, it is subject to the risk that market rates of interest will increase
before the time the security is delivered, with the result that the yield on the
security delivered to the Fund may be lower than the yield available on other,
comparable securities at the time of delivery. If the Fund has outstanding
obligations to buy when-issued securities, it will maintain liquid assets in a
segregated account at its custodian bank in an amount sufficient to satisfy
these obligations.

FOREIGN SECURITIES
- ------------------

Foreign securities may present risks not associated with investments in
comparable securities of U.S. issuers. There may be less information publicly
available about a foreign corporate or governmental issuer than about a U.S.
issuer, and foreign issuers are not generally subject to accounting, auditing
and financial reporting standards and practices comparable to those in the
United States. The securities of some foreign issuers are less liquid and at
times more volatile than securities of comparable U.S. issuers. Foreign
brokerage commissions and securities custody costs are often higher than in the
United States. With respect to certain foreign countries, there is a
possibility of governmental expropriation of assets, confiscatory taxation,
political or financial instability and diplomatic developments that could affect
the value of investments in those countries. The Fund's receipt of interest on
foreign government securities may depend on the availability of tax or other
revenues to satisfy the issuer's obligations. The remedies of the Fund may be
extremely limited if a foreign issuer defaults on its obligations. In addition,
the operations and results of foreign issuers and domestic issuers with
operations abroad may be affected favorably or unfavorably by changes in
currency exchange rates or exchange control regulations.

Since most foreign securities are denominated in foreign currencies or
traded primarily in securities markets in which settlements are made in foreign
currencies, the value of these investments and the net investment income
available for distribution to shareholders of the Fund may be affected favorably
or unfavorably by changes in currency exchange rates, exchange control
regulations or foreign withholding taxes. Changes in the value relative to the
U.S. dollar of a foreign currency in which the Fund's holdings are denominated
or foreign witholding taxes will result in a change in the U.S. dollar value of
the Fund's assets and the Fund's income available for distribution.

YEAR 2000
- ---------

-8-
<PAGE>

these goals will not be achieved. Similarly, the values of certain of the
portfolio securities held by the Fund may be adversely affected by the inability
of the securities' issuers or of third parties to process this type of
information properly.

THE FUND'S INVESTMENT ADVISER

The Fund's investment adviser is Loomis Sayles, One Financial Center,
Boston, Massachusetts 02111. Founded in 1926, Loomis Sayles is one of the
country's oldest and largest investment firms.

In addition to selecting and reviewing the Fund's investments, Loomis
Sayles provides executive and other personnel for the management of the Fund.
The Board of Trustees supervises Loomis Sayles's conduct of the affairs of the
Fund.

The portfolio manager for the Fund is Anthony J. Wilkins. Mr. Wilkins
joined Loomis Sayles in 1990 and is a Director and Vice President of the
firm.

FUND EXPENSES

The Fund pays Loomis Sayles a monthly investment advisory fee. This fee is
paid at the annual rate of .40% of the Fund's average weekly net assets.

PORTFOLIO TRANSACTIONS

Loomis Sayles selects brokers and dealers to execute portfolio transactions
for the Fund. Portfolio turnover considerations will not limit Loomis Sayles's
investment discretion in managing the Fund's assets. The Fund anticipates that
its portfolio turnover rates will vary significantly from time to time depending
on the volatility of economic and market conditions. High portfolio turnover
may result in higher costs such as higher brokerage commissions and higher
levels of taxable gains. See "Dividends, Capital Gains Distributions and Taxes"
for information on the tax consequences of investing in the Fund.

HOW TO PURCHASE SHARES

You may make an initial purchase of shares of the Fund by submitting a
completed application form and payment to Loomis Sayles.

The minimum initial investment in the Fund is $2,000,000. Subsequent
investments must be at least $50,000. The Trust reserves the right to waive
these minimums in its sole discretion.

-9-
<PAGE>

is subject in each case to the determination by Loomis Sayles that the
securities to be exchanged are acceptable for purchase by the Fund. Securities
accepted by Loomis Sayles in exchange for Fund shares will be valued in the same
manner as the Fund's assets as described below as of the time of the Fund's next
determination of net asset value after such acceptance. All dividends and
subscription or other rights which are reflected in the market price of accepted
securities at the time of valuation become the property of the Fund and must be
delivered to the Fund upon receipt by the investor from the issuer. A gain or
loss for federal income tax purposes would be realized upon the exchange by an
investor that is subject to federal income taxation, depending upon the
investor's basis in the securities tendered. A shareholder who wishes to
purchase shares by exchanging securities should obtain instructions by calling
(617) 482-2450.

Loomis Sayles will not approve the acceptance of securities in exchange for
shares of the Fund unless (1) Loomis Sayles, in its sole discretion, believes
the securities are appropriate investments for the Fund; (2) the investor
represents and agrees that all securities offered to the Fund can be resold by
the Fund without restriction under the Securities Act of 1933, as amended, or
otherwise; and (3) the securities are eligible to be acquired under the Fund's
investment policies and restrictions. No investor owning 5% or more of the
Fund's shares may purchase additional Fund shares by the exchange of securities.

Upon acceptance of your order, the Trust opens an account for you, applies
the payment to the purchase of full and fractional Fund shares and mails a
statement of the account confirming the transaction. After an account has been
established, you may send subsequent investments at any time.

The Trust reserves the right to reject any purchase order for any reason
which the Trust in its sole discretion deems appropriate. Although the Trust
does not anticipate that it will do so, the Trust reserves the right to suspend
or change the terms of the offering of its shares.

The price you pay will be the per share net asset value next calculated
after a proper investment order is received by the Trust. Shares of the Fund are
sold without any sales charge. The net asset value of the Fund's shares is
calculated by dividing the Fund's net assets by the number of shares
outstanding. Net asset value is calculated at least weekly and as of the close
of the New York Stock Exchange (the "Exchange") on each day on which an order
for purchase or redemption of Fund shares is received and on which the Exchange
is open for unrestricted trading. Portfolio securities are valued at their
market value as more fully described in the Statement of Additional Information.

HOW TO REDEEM SHARES

You can redeem your shares by sending a written request to the Trust.

Proceeds resulting from a written redemption request will normally be
mailed to you within seven days after receipt of your request in good order. If
you purchased your shares by check and your check was deposited less than
fifteen days prior to the redemption request, the Trust may withhold redemption
proceeds until your check has cleared.

Redemption proceeds may be made in money or in kind, or partly in money and
partly in kind, as determined by the Trust.

The Fund may suspend the right of redemption and may postpone payment for
more than seven days when the Exchange is closed for other than weekends or
holidays, or if permitted by the rules of the SEC when trading on the Exchange
is restricted or during an emergency which makes it impracticable for the Fund
to dispose of its securities or to determine fairly the value of its net assets,
or during any other period permitted by the SEC for the protection of investors.

-10-
<PAGE>

OTHER INFORMATION

As of March 31, 1998, Trustees of Clark University may be deemed to control
the Fund because it possessed beneficial ownership, either directly or
indirectly, of more than 25% of the Fund's shares.

The Fund's investment performance may from time to time be included in
advertisements about the Fund.

The Fund's yield will be computed by dividing the Fund's net investment
income for a recent 30-day period by the maximum offering price (reduced by any
undeclared earned income expected to be paid shortly as a dividend) on the last
trading day of that period.

Total return for the Fund is measured by comparing the value of an
investment in the Fund at the beginning of the relevant period to the redemption
value of the investment in the Fund at the end of the period (assuming immediate
reinvestment of any dividends or capital gain distributions).

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES

Because the Fund is designed primarily for tax-exempt investors such as
pension plans, endowments and foundations, the Fund is not managed with a view
to reducing taxes. The Fund pays any net investment income to shareholders as
dividends monthly. The Fund also distributes all of its net realized capital
gains after applying any capital loss carryovers. Any capital gain
distributions are normally made annually in December, but may, to the extent
permitted by law, be made more frequently as deemed advisable by the Trustees.
The Trustees may change the frequency with which the Fund declares or pays
dividends.

Income dividends and short-term capital gain distributions are treated as
ordinary income to you whether distributed in cash or additional shares.
Distributions designated by the Fund as deriving from net gains on securities
held for more than one year but not more than 18 months and from net gains on
securities held for more than 18 months will be taxable as such whether
distributed in cash or additional shares and regardless of how long you have
held your shares. However, any loss recognized by you on the taxable disposition
of shares held for six months or less will be treated as a long-term capital
loss to the extent of any capital gain distribution you received with respect to
the shares.

-11-
<PAGE>

In January of each year, the Trust will send you a statement showing the
federal tax status of dividends and distributions paid to you during the
preceding year.

The foregoing summarizes certain U.S. federal income tax consequences of
investing in the Fund. Before investing, you should consult your own tax
adviser for more information concerning the federal, foreign, state and local
tax consequences of investing in, redeeming or exchanging Fund shares.

-12-
<PAGE>

APPENDIX A
DESCRIPTION OF BOND RATINGS ASSIGNED BY

STANDARD & POOR'S AND
MOODY'S INVESTORS SERVICE, INC.

STANDARD & POOR'S
-----------------

AAA

This is the highest rating assigned by Standard & Poor's to a debt obligation
and indicates an extremely strong capacity to pay interest and repay principal.

Bonds rated A have a strong capacity to pay interest and repay principal,
although they are somewhat more susceptible to the adverse effects of changes
in circumstances and economic conditions than obligations in higher rated
categories.

BBB

Bonds rated BBB are regarded as having an adequate capacity to pay interest and
repay principal. Whereas they normally exhibit adequate protection parameters,
adverse economic conditions or changing circumstances are more likely to lead
to a weakened capacity to repay principal and pay interest for bonds in this
category than for bonds in higher rated categories.

BB, B, CCC, CC

Bonds rated BB, B, CCC and CC are regarded, on balance, as predominantly
speculative with respect to capacity to pay interest and repay principal in
accordance with the terms of the obligation. BB indicates the lowest degree of
speculation and CC the highest degree of speculation. While such bonds will
likely have some quality and protective characteristics, these are outweighed
by large uncertainties or major risk exposures to adverse conditions.

The rating C is reserved for income bonds on which no interest is being paid.

Bonds rated D are in default, and payment of interest and/or repayment of
principal is in arrears.

This symbol is attached to the ratings of instruments with significant
noncredit risks such as risks to principal or volatility of expected returns.

Plus (+) or Minus (-): The ratings from "AA" to "B" may be modified by the
addition of a plus or minus sign to show relative standing within the major
rating categories.

A-1
<PAGE>

MOODY'S INVESTORS SERVICE, INC.
-------------------------------

AAA

Bonds that are rated Aa are judged to be high quality by all standards.
Together with the Aaa group they comprise what are generally known as high
grade bonds. They are rated lower than the best bonds because margins of
protection may not be as large as in Aaa securities or fluctuation of
protective elements may be of greater amplitude or there are other elements
present that make the long-term risks appear somewhat larger than in Aaa
securities.

Bonds that are rated A possess many favorable investment attributes and are to
be considered as upper medium grade obligations. Factors giving security to
principal and interest are considered adequate, but elements may be present
that suggest a susceptibility to impairment sometime in the future.

BAA

Bonds which are rated Ba are judged to have speculative elements; their future
cannot be considered as well assured. Often, the protection of interest and
principal payments may be very moderate, and thereby not well safeguarded
during both good and bad times over the future. Uncertainty of position
characterizes bonds in this class.

CAA

Bonds which are rated Caa are of poor standing. Such issues may be in default
or there may be present elements of danger with respect to principal or
interest.

Bonds which are rated Ca represent obligations which are speculative in a high
degree. Such issues are often in default or have other marked shortcomings.

Bonds which are rated C are the lowest rated class of bonds, and issues so
rated can be regarded as having extremely poor prospects of ever attaining any
real investment standing.

Should no rating be assigned by Moody's, the reason may be one of the
following:

A-2
<PAGE>

1. An application for rating was not received or accepted.

2. The issue or issuer belongs to a group of securities that are
not rated as a matter of policy.

3. There is lack of essential data pertaining to the issue or
issuer.

4. The issue was privately placed in which case the rating is not
published in Moody's publications.

Suspension or withdrawal may occur if new and material circumstances arise, the
effects of which preclude satisfactory analysis; if there is no longer
available reasonable up-to-date data to permit a judgment to be formed; if a
bond is called for redemption; or for other reasons.

A-3
<PAGE>

APPENDIX B
DESCRIPTION OF
FITCH CMO V-RATINGS

A Fitch CMO market risk rating is an opinion as to the relative sensitivity of
a security's price and cash flows to changes in interest rates and, where
relevant, other market conditions. INVESTORS SHOULD UNDERSTAND THAT SECURITIES
WITH RATINGS REFLECTING EVEN THE LOWEST MARKET RISK ARE LIKELY TO EXPERIENCE
LOSSES IN THE EVENT OF ADVERSE CHANGES IN MARKET CONDITIONS. Fitch's market
risk ratings are based on information provided to Fitch by sources deemed to be
reliable, however, Fitch does not verify the accuracy of this underlying
information. These ratings do not constitute recommendations to purchase, sell
or hold any securities, as they do not comment on the adequacy of market prices
or the suitability of any security for any investor.

<TABLE>
<CAPTION>
V-Rating Representative Distribution Description
- ---------- --------------------------- -----------
<S> <C> <C>
V-1 PAC classes with wide prepayment Market Risk: Low
collars, short duration floaters and
V-2 short duration sequential. Securities rated V-1 and V-2 perform
consistently across a range of interest rate
scenarios. These securities exhibit interest rate
risk comparable to short duration treasuries (1-5
years).

V-3 Medium duration Floater, Short Market Risk: Moderate
duration TAC, Short duration PAC
V-4 II, Long duration PAC I. Securities rated V-3 and V-4 have relatively
consistent performance across a range of interest
rate scenarios. These securities experience
interest rate risk comparable to long duration
treasuries (10-30 years).

V-5 PAC classes with narrow collars, Market Risk: Moderate to High
support classes, accrual bonds and
V-6 short duration IO's and PO's, Z Securities rated V-5, V-6 and V-7 experience
bond's. significant variations in performance across a
V-7 range of interest rate scenarios. These securities
have substantial excess interest rate risk and in
many instances exhibit negative convexity. Z
bond's with durations comparable to treasury
zero-coupon issues also fall in this range.

V-8 Leveraged inverse floaters, long Market Risk: High to Speculative
</TABLE>

B-1

<PAGE>

V-9 duration IO's and PO's, super PO's, Securities rated V-8, V-9 and V-10 experience
jump Zs. sharp, severe variations in performance across a
V-10 range of interest rate scenarios. These securities
exhibit risk characteristics such as extreme
negative convexity, significant sensitivity to the
direction of interest rate movements, and highly
leveraged sensitivity to interest rate indices.
</TABLE>

s:\lsit\prosp&sa\1998\intdurpr.wpd

<PAGE>

LOOMIS SAYLES INVESTMENT GRADE FIXED INCOME FUND
ONE FINANCIAL CENTER
BOSTON, MASSACHUSETTS 02111
(617) 482-2450

PROSPECTUS

APRIL 22, 1998

The Loomis Sayles Investment Trust (the "Trust") is a group of seven mutual
funds including the Loomis Sayles Investment Grade Fixed Income Fund (the
"Fund"). The other series, which are described in separate prospectuses,
are:

TABLE OF CONTENTS

<TABLE>
<S> <C>
SUMMARY OF EXPENSES...................................................... - 3 -

FINANCIAL HIGHLIGHTS..................................................... - 4 -

PRIOR PERFORMANCE........................................................ - 5 -

THE TRUST................................................................ - 6 -

INVESTMENT OBJECTIVE AND POLICIES........................................ - 6 -

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS............................ - 7 -

THE FUND'S INVESTMENT ADVISER............................................ - 11 -

FUND EXPENSES............................................................ - 11 -

PORTFOLIO TRANSACTIONS................................................... - 12 -

HOW TO PURCHASE SHARES................................................... - 12 -

HOW TO REDEEM SHARES..................................................... - 13 -

OTHER INFORMATION........................................................ - 13 -

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES.......................... - 14 -

APPENDIX A -A-1-
</TABLE>

-2-
<PAGE>

SUMMARY OF EXPENSES

<TABLE>
<S> <C>
Shareholder Transaction Expenses:
Maximum Sales Load Imposed on
Purchases (as a percentage of offering price) none
Maximum Sales Load Imposed on
Reinvested Dividends (as a percentage of
offering price) none
Deferred Sales Load (as a percentage of original
purchase price or redemption
proceeds, as applicable) none
Redemption Fees (as a percentage of amount redeemed) none
Exchange Fees none

Annual Fund Operating Expenses
(as a percentage of average net assets)
Management Fees (after expense limitation) .40%
12b-1 Fees none
Other Operating Expenses/1/ .15%
Total Fund Operating Expenses (after expense
limitation)/1/ .55%

Example
You would pay the following
expenses on a $1,000 investment
assuming a 5% annual return
(with or without a redemption at
the end of each time period):

One Year $ 6
Three Years $18
Five Years $31
Ten Years $69
</TABLE>

________________________________

/1/ Loomis Sayles has voluntarily undertaken for an indefinite
period to limit the Fund's total Fund operating expenses to the percentage of
average net assets shown above. In the absence of the voluntary expense
limitation, Other Operating Expenses and Total Fund Operating Expenses for the
fiscal year ended December 31, 1997 would have been 0.29% and 0.69%,
respectively.

-3-
<PAGE>

FINANCIAL HIGHLIGHTS

<TABLE>
<CAPTION>
March 7+ through
December 31,
-------------
1997
- -----
<S> <C>
Net asset value, beginning of period......................... $ 11.72

Income from investment operations -
Net investment income..................................... 0.67
Net realized and unrealized gain (loss) on investments.... 0.48
-------
Total from investment operations....................... 1.15

Less distributions -
Dividends from net investment income...................... (0.67)
Distributions from net realized capital gains............. (0.14)
-------
Total distributions.................................... (0.81)
-------
Net asset value, end of period............................... $ 12.06
=======

Total return (%)............................................. 10.1**
Net assets, end of period (000).............................. $82,964
Ratio of operating expenses to average net assets (%)........ 0.55*
Ratio of net investment income to average net assets (%)..... 6.91*
Portfolio turnover rate (%).................................. 39.0**
Without giving effect to the voluntary expense limitations:
The ratio of operating expenses to average net assets
would have been (%).................................... 0.70*
The net investment income per share would have been....... $ 0.66
</TABLE>

+Date of effectiveness of the Fund's registration statement under the
Securities Act of 1933, as amended.
*Annualized.
**Not annualized.

-4-
<PAGE>

PRIOR PERFORMANCE

(FOR A SHARE OF THE FUND OUTSTANDING THROUGHOUT THE INDICATED PERIODS)

The information presented below, for the periods indicated, relates to periods
prior to the effectiveness of the Fund's registration statement under the
Securities Act of 1933, as amended (the "1933 Act"). The following information
should be read in conjunction with the financial highlights, financial
statements, and notes thereto that have been audited by Coopers & Lybrand,
L.L.P., independent accountants, whose report thereon appears in the Fund's 1997
Annual Report, which is incorporated by reference into this Prospectus and the
Statement of Additional Information. The Fund is managed in a manner that is in
all material respects similar to the manner in which it was managed prior to the
effectiveness of its registration statement under the 1933 Act.

<TABLE>
<CAPTION>
January 1, 1997 Year Ended Year Ended July 1* through
through March 6, December 31, December 31, December 31,
1997 1996 1995 1994
---- ---- ---- ----
<S> <C> <C> <C> <C>
Net asset value,
beginning of period.......................... $ 11.81 $ 11.56 $ 9.57 $ 10.00

Income from investment operations -
Net investment income......................... 0.15 0.80 0.75 0.41
Net realized and unrealized gain (loss)
on investments............................... (0.10) 0.40 2.05 (0.43)
-------- ------- ------- ---------
Total from investment operations........... 0.05 1.20 2.80 (0.02)

Less distributions -
Dividends from net investment income........... (0.14) (0.79) (0.76) (0.41)
Distributions from net realized
capital gains.............................. 0.00 (0.16) (0.05) 0.00
-------- ------- ------- ---------
Total distributions......................... (0.14) (0.95) (0.81) (0.41)
-------- ------- ------- ---------
Net asset value, end of period.................. $ 11.72 $ 11.81 $ 11.56 $ 9.57
======== ======= ======= =========

Total return (%)................................ 0.4*** 10.9 30.3 (0.3)***
Net assets, end of period (000)................. $ 52,315 $51,752 $21,816 $ 4,649
Ratio of operating expenses to
average net assets (%)....................... 0.55** 0.55 0.55 0.55**
Ratio of net investment income to
average net assets (%)........................ 7.30** 7.27 7.61 8.18**
Portfolio turnover rate (%)..................... 21.2*** 73.8 21.6 112.0***
Without giving effect to the
voluntary expense limitations:
The ratio of operating expenses to average
net assets would have been (%).......... 0.62** 0.70 0.94 1.55**
The net investment income per share
would have been.......................... $ 0.15 $ 0.78 $ 0.71 $ 0.36
</TABLE>

* Commencement of operations.
** Annualized.
***Not annualized.

-5-
<PAGE>

THE TRUST

INVESTMENT OBJECTIVE AND POLICIES

The Fund's investment objective is above-average total investment return
through a combination of current income and capital appreciation.

The Fund seeks to achieve its objective by investing in a diversified
portfolio of debt securities, although up to 20% of its assets may be invested
in preferred stocks. Under normal market conditions, the Fund will invest at
least 65% of its total assets in fixed income securities that are of investment
grade quality at the time of purchase. Debt securities may include corporate
securities, securities issued or guaranteed by the U.S. Government, its
authorities, agencies or instrumentalities, or certificates representing
undivided interests in the interest or principal of U.S. Treasury securities
("U.S. Government Securities"), zero coupon securities, collateralized mortgage
securities and when-issued securities (including interest-only and principal-
only ("IOs" and "POs") classes of mortgage-backed securities), which are
described herein (together with their related risks) under "More Information
About the Fund's Investments." The Fund will normally invest at least 90% of
its assets in investment grade securities. Investment grade securities include
those rated BBB and above by Standard & Poor's ("S&P") or Baa and above by
Moody's Investors Service, Inc. ("Moody's") or unrated securities that Loomis
Sayles has determined to be of comparable quality. The Fund may continue to
hold securities that are downgraded in quality subsequent to their purchase if,
in the opinion of Loomis Sayles, it would be advantageous to do so. The Fund
may invest a portion of its assets in securities of Canadian issuers, and a
limited portion of its assets in securities of other foreign issuers. See "More
Information About the Fund's Investments; Foreign Securities."

The percentages of the Fund's net assets invested during the fiscal year
ended December 31, 1997 in securities assigned to the various rating categories
by S&P and Moody's on a dollar-weighted basis were approximately as follows:
"AAA"/"Aaa," 21.9%; "AA"/"Aa," 8.1%; "A"/"A," 16.4%; "BBB"/"Baa," 42.6%;
"BB"/"Ba," 9.6%; "B"/"B," 1.4%; and below "B," 0%. The percentage of the Fund's
net assets invested during such fiscal year in unrated debt securities as a
group was approximately 2.44%. The percentages of the Fund's net assets
invested during such fiscal year in such unrated securities (categorized by
comparable rating category) were approximately as follows: "AAA"/"Aaa," 0%;
"AA"/"Aa," 0.76%; "A"/"A," 0.12%; "BBB"/"Baa," 0%; "BB"/"Ba," 1.56%; "B"/"B,"
0%; and below "B," 0%.

Some of the Fund's investment restrictions are "fundamental" and cannot be
changed without a majority vote of the Fund's shareholders. Such restrictions
include: (1) a restriction prohibiting the Fund from making loans; (2) a
restriction prohibiting the Fund from purchasing a security (other than U.S.
Government Securities) if, as a result, more than 25% of the Fund's total assets
(taken at current value) would be invested in any one industry; (3) a
restriction prohibiting the Fund from borrowing money in excess of 10% of its
total assets (taken at cost) or 5% of its total assets (taken at current value),
whichever is lower, and from borrowing any money except as a temporary measure
for extraordinary or emergency purposes; and (4) a restriction prohibiting the
Fund from purchasing any illiquid security including a security that is not
readily marketable if, as a result, more than 15% of the Fund's net assets based
on current value would then be invested in such security. For additional
investment restrictions, see the Statement of Additional Information.

-6-
<PAGE>

The investment objective of the Fund is " fundamental" and cannot be
changed without a majority vote of the Fund's shareholders. All investment
policies other than those that are identified as "fundamental" may be changed by
the Trustees without a vote of the Fund's shareholders.

MORE INFORMATION ABOUT THE FUND'S INVESTMENTS

The net asset value of the Fund's shares will vary as a result of changes
in the value of securities in the Fund's portfolio. The following describes the
types of securities in which the Fund will principally invest and the risks
associated with them. Additional information about the Fund's investment
practices can be found in the Statement of Additional Information.

FIXED INCOME SECURITIES
- -----------------------

The Fund may invest in fixed income securities of any maturity. Fixed
income securities pay a specified rate of interest or dividends. Fixed income
securities include securities issued by federal, state, local and foreign
governments and related agencies, and by a wide range of foreign and domestic
private issuers. The Fund may also invest in other debt securities that pay a
rate of interest or dividends that is adjusted periodically by reference to some
specified index or market rate. Such securities are included within the
definition of fixed income securities as used in this Prospectus other than for
purposes of determining compliance with the Fund's investment policy of
investing, under normal market conditions, at least 65% of its total assets in
investment grade fixed income securities. Because interest rates vary, it is
impossible to predict the income of the Fund for any particular period.

Fixed income securities are subject to market and credit risk. Market risk
relates to changes in a security's value as a result of changes in interest
rates generally. In general, the values of fixed income securities increase
when prevailing interest rates fall and decrease when interest rates rise.
Credit risk relates to the ability of the issuer to make payments of principal
and interest. Generally, the longer the maturity of a fixed income security,
the greater the fluctuations in its value because of market and credit risk.

U.S. GOVERNMENT SECURITIES
- --------------------------

Although U.S. Government Securities generally do not involve the credit
risks associated with other types of fixed income securities, the market values
of U.S. Government Securities will fluctuate as interest rates change. Thus,
for example, the value of an investment in U.S. Government Securities may fall
during times of rising interest rates. Yields on U.S. Government Securities tend
to be lower than those of other fixed income securities of comparable
maturities.

-7-
<PAGE>

securities are generally more volatile investments than many other fixed income
securities. See "Collateralized Mortgage Obligations" below for additional
information regarding the risks associated with mortgage-backed securities.

In addition to investing directly in U.S. Government Securities, the Fund
may purchase certificates of accrual or similar instruments ("strips")
evidencing undivided ownership interests in interest payments or principal
payments, or both, in U.S. Treasury securities. These investment instruments
may be highly volatile.

ZERO COUPON SECURITIES
- ----------------------

COLLATERALIZED MORTGAGE OBLIGATIONS
- -----------------------------------

The Fund may invest in collateralized mortgage obligations ("CMOs"). A CMO
is a limited recourse security backed by a portfolio of mortgages or, more
typically, by mortgage-backed securities held under an indenture. CMOs may be
issued by instrumentalities of the U.S. Government or by non-governmental
entities. The issuer's obligation to make interest and principal payments is
derived from and secured by the underlying portfolio of mortgages or mortgage-
backed securities. CMOs are issued with a number of classes or series which
have different maturities and which may represent interests in some or all of
the interest or principal payments on the underlying collateral or a combination
thereof. CMOs of different classes or series are generally retired in sequence
as the underlying mortgage loans in the mortgage pool are repaid. In the event
of sufficient early prepayments on such mortgages, the class or series of CMOs
first to mature generally will be retired prior to its maturity. As with other
mortgage-backed securities, the early retirement of a particular class or series
of CMOs held by the Fund could involve the loss of any premium the Fund paid
when it acquired the investment and could result in the Fund's reinvesting the
proceeds at a lower interest rate than the interest rate paid by the retired
CMO. A faster than anticipated rate of prepayments will generally result in
losses on CMO's representing interests in the interest payments on the
underlying portfolio of mortgage-backed securities. Because of the early
retirement feature, CMOs may be more volatile than many other fixed income
investments. In addition, slower than anticipated prepayments on the underlying
mortgages can extend the effective maturities of CMOs, subjecting them to a
greater risk of decline in market value in response to rising interest rates
than traditional debt securities.

COMMERCIAL MORTGAGE-BACKED SECURITIES
- -------------------------------------

Commercial mortgage-backed securities are generally structured similarly to
pass-through securities or to CMOs, although other structures are possible.
They may pay fixed or adjustable rates of interest. Commercial mortgage-backed
securities have been issued in public or private transactions by a variety of
public and private issuers.

-8-
<PAGE>

Assets underlying commercial mortgage-backed securities may relate only to a few
properties or a single property. The risk involved in single property financings
is highly concentrated. In addition, commercial properties, particularly
industrial and warehouse properties, are subject to environmental risks and the
burdens and costs of compliance with environmental laws and regulations. At the
same time, commercial mortgage-backed securities may have a lower prepayment
risk than residential mortgage-backed securities, because commercial mortgage
loans generally prohibit or impose penalties on prepayments of principal. In
addition, commercial mortgage-backed securities often are structured with some
form of credit enhancement to protect against potential losses on the underlying
mortgage loans.

STRIPPED MORTGAGE-BACKED SECURITIES
- -----------------------------------

WHEN-ISSUED SECURITIES
- ----------------------

The Fund may purchase securities on a "when-issued" basis. This means that
the Fund will enter into a commitment to buy the security before the security
has been issued. The Fund's payment obligation and the interest rate on the
security are determined when the Fund enters into the commitment. The security
is typically delivered to the Fund 15 to 120 days later. No interest accrues on
the security between the time the Fund enters into the commitment and the time
the security is issued. If the value of the security being purchased falls
between the time the Fund commits to buy it and the payment date, the Fund may
sustain a loss. The risk of this loss is in addition to the Fund's risk of loss
on the securities actually held in its portfolio at the time. When the Fund
buys a security on a when-issued basis, it is subject to the risk that market
rates of interest will increase before the time the security is delivered, with
the result that the yield on the security delivered to the Fund may be lower
than the yield available on other, comparable securities at the time of
delivery. If the Fund has outstanding obligations to buy when-issued
securities, it will maintain liquid assets in a segregated account at its
custodian bank in an amount sufficient to satisfy these obligations.

CONVERTIBLE SECURITIES
- ----------------------

Convertible securities include corporate bonds, notes or preferred stocks
of U.S. or foreign issuers that can be converted into (that is, exchanged for)
common stocks or other equity securities at a stated price or rate. Convertible
securities also include other securities, such as warrants, that provide an
opportunity for equity participation. Because convertible securities can be
converted into equity securities, their value will normally vary in some
proportion with those of the underlying equity securities. Convertible
securities usually provide a higher yield than the underlying equity security,
however, so that when the price of the underlying equity security falls, the
decline in the price of the convertible security may sometimes be less
substantial than that of the underlying equity security. Due to the conversion
feature, convertible securities generally yield less than nonconvertible fixed
income securities of similar credit quality and maturity. The Fund's investment
in convertible securities may at times include securities that have a mandatory
conversion feature, pursuant to which the securities convert automatically into
common stock at a specified date and conversion ratio, or that are convertible
at the option of the issuer. Because conversion is not at the option of the
holder, the Fund may be required to convert the security into the underlying
common stock even at times when the value of the underlying common stock has
declined substantially.

-9-
<PAGE>

FOREIGN SECURITIES
- ------------------

Foreign securities may present risks not associated with investments in
comparable securities of U.S. issuers. There may be less information publicly
available about a foreign corporate or governmental issuer than about a U.S.
issuer, and foreign issuers are not generally subject to accounting, auditing
and financial reporting standards and practices comparable to those in the
United States. The securities of some foreign issuers are less liquid and at
times more volatile than securities of comparable U.S. issuers. Foreign
brokerage commissions and securities custody costs are often higher than in the
United States. With respect to certain foreign countries, there is a
possibility of governmental expropriation of assets, confiscatory taxation,
political or financial instability and diplomatic developments that could affect
the value of investments in those countries. The Fund's receipt of interest on
foreign government securities may depend on the availability of tax or other
revenues to satisfy the issuer's obligations. In addition, the remedies of the
Fund may be extremely limited if a foreign issuer defaults on its obligations.

Since most foreign securities are denominated in foreign currencies or
traded primarily in securities markets in which settlements are made in foreign
currencies, the value of these investments and the net investment income
available for distribution to shareholders of the Fund may be affected favorably
or unfavorably by changes in currency exchange rates, exchange control
regulations or foreign withholding taxes. Changes in the value relative to the
U.S. dollar of a foreign currency in which the Fund's holdings are denominated
will result in a change in the U.S. dollar value of the Fund's assets and the
Fund's income available for distribution.

LOWER RATED FIXED INCOME SECURITIES
- -----------------------------------

-10-
<PAGE>

the secondary market for higher rated fixed income securities. This lack of
liquidity at certain times may affect the values of these securities and may
make the valuation and sale of these securities by the Fund more difficult.
Certain lower rated fixed income securities do not pay interest on a current
basis. However, the Fund will accrue and distribute this interest on a current
basis, and may be required to sell securities at times when Loomis Sayles would
not otherwise deem it advisable to do so in order to generate cash for
distributions. Securities of below investment grade quality are commonly
referred to as "junk bonds." Securities in the lowest rating categories may be
in poor standing or in default. Investment grade fixed income securities may
share some of the characteristics of lower rated fixed income securities
described above.

YEAR 2000
- ---------

THE FUND'S INVESTMENT ADVISER

The Fund's investment adviser is Loomis Sayles, One Financial Center,
Boston, Massachusetts 02111. Founded in 1926, Loomis Sayles is one of the
country's oldest and largest investment firms.

In addition to selecting and reviewing the Fund's investments, Loomis
Sayles provides executive and other personnel for the management of the Fund.
The Board of Trustees supervises Loomis Sayles's conduct of the affairs of the
Fund.

FUND EXPENSES

The Fund pays Loomis Sayles a monthly investment advisory fee. This fee is
paid at the annual rate of 0.40% of the Fund's average daily net assets.

-11-
<PAGE>

Loomis Sayles has voluntarily undertaken for an indefinite period to waive
its fees and, to the extent necessary, to bear other Fund expenses in order to
limit the Fund's total operating expenses to .55% of average annual net assets.

PORTFOLIO TRANSACTIONS

HOW TO PURCHASE SHARES

You may make an initial purchase of shares of the Fund by submitting a
completed application form and payment to Loomis Sayles.

The minimum initial investment in the Fund is $3,000,000. Subsequent
investments must be at least $50,000. The Trust reserves the right to waive
these minimums in its sole discretion.

Shares of the Fund may be purchased by exchange of (i) cash, (ii)
securities on deposit with a custodian acceptable to Loomis Sayles or (iii) a
combination of such securities and cash. Purchase of shares of the Fund in
exchange for securities is subject in each case to the determination by Loomis
Sayles that the securities to be exchanged are acceptable for purchase by the
Fund. Securities accepted by Loomis Sayles in exchange for Fund shares will be
valued in the same manner as the Fund's assets, as described below, as of the
time of the Fund's next determination of net asset value after such acceptance.
All dividends and subscription or other rights which are reflected in the market
price of accepted securities at the time of valuation become the property of the
Fund and must be delivered to the Fund upon receipt by the investor from the
issuer. A gain or loss for federal income tax purposes would be realized upon
the exchange by an investor that is subject to federal income taxation,
depending upon the investor's basis in the securities tendered. A shareholder
who wishes to purchase shares by exchanging securities should obtain
instructions by calling (617) 482-2450.

Upon acceptance of your order, the Trust opens an account for you, applies
the payment to the purchase of full and fractional Fund shares and mails a
statement of the account confirming the transaction. After an account has been
established, you may send subsequent investments at any time.

The Trust reserves the right to reject any purchase order for any reason
which the Trust in its sole discretion deems appropriate. Although the Trust
does not anticipate that it will do so, the Trust reserves the right to suspend
or change the terms of the offering of its shares.

-12-
<PAGE>

by dividing the Fund's net assets by the number of shares outstanding. Net asset
value is calculated at least weekly and as of the close of the New York Stock
Exchange (the "Exchange") on each day on which an order for purchase or
redemption of Fund shares is received and on which the Exchange is open for
unrestricted trading. Portfolio securities are valued at their market value as
more fully described in the Statement of Additional Information.

HOW TO REDEEM SHARES

You can redeem your shares by sending a written request to the Trust.

Proceeds resulting from a written redemption request will normally be
mailed to you within seven days after receipt of your request in good order. If
you purchased your shares by check and your check was deposited less than
fifteen days prior to the redemption request, the Trust may withhold redemption
proceeds until your check has cleared.

Redemption proceeds may be made in money or in kind, or partly in money and
partly in kind, as determined by the Trust.

The Fund may suspend the right of redemption and may postpone payment for
more than seven days when the Exchange is closed for other than weekends or
holidays, or if permitted by the rules of the SEC when trading on the Exchange
is restricted or during an emergency which makes it impracticable for the Fund
to dispose of its securities or to determine fairly the value of its net assets,
or during any other period permitted by the SEC for the protection of investors.

OTHER INFORMATION

The Trustees may, without shareholder approval, divide the Trust's shares
of beneficial interest into multiple series. The Trust is currently divided
into seven series, including the Fund and the other funds listed on the cover of
this Prospectus.

The Fund's investment performance may from time to time be included in
advertisements about the Fund.

The Fund's yield will be computed by dividing the Fund's net investment
income for a recent 30-day period by the maximum offering price (reduced by any
undeclared earned income expected to be paid shortly as a dividend) on the last
trading day of that period.

Total return for the Fund is measured by comparing the value of an
investment in the Fund at the beginning of the relevant period to the redemption
value of the investment in the Fund at the end of the period (assuming immediate
reinvestment of any dividends or capital gain distributions).

-13-
<PAGE>

portfolio and the Fund's operating expenses. Investment performance also often
reflects the risks associated with the Fund's investment objectives and
policies. These factors should be considered when comparing the Fund's
investment results with those of other mutual funds and other investment
vehicles. Quotations of investment performance for any period when an expense
limitation was in effect will be greater than if the limitation had not been in
effect.

DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAXES

Because the Fund is designed primarily for tax-exempt investors such as
pension plans, endowments and foundations, the Fund is not managed with a view
to reducing taxes. The Fund pays any net investment income to shareholders as
monthly dividends. The Fund also distributes all of its net realized capital
gains after applying any capital loss carryovers. Any capital gain
distributions are normally made annually in December, but may, to the extent
permitted by law, be made more frequently as deemed advisable by the Trustees.
The Trustees may change the frequency with which the Fund declares or pays
dividends.

The Fund intends to qualify as a "regulated investment company" under the
Internal Revenue Code of 1986, as amended. As such, so long as the Fund
distributes substantially all its net investment income and net realized capital
gains to its shareholders on a current basis, the Fund itself does not pay any
federal income or excise tax. The Fund intends to make sufficient distributions
to be relieved of federal taxes.

Income dividends and short-term capital gain distributions are treated as
ordinary income to you whether distributed in cash or additional shares.
Distributions designated by the Fund as deriving from net gains on securities
held for more than one year but not more than 18 months and from net gains on
securities held for more than 18 months will be taxable as such whether
distributed in cash or additional shares and regardless of how long you have
held your shares. However, any loss recognized by you on the taxable
disposition of shares held for six months or less will be treated as a long-term
capital loss to the extent of any capital gain distribution you received with
respect to the shares.

In January of each year, the Trust will send you a statement showing the
federal tax status of dividends and distributions paid to you during the
preceding year.

The foregoing summarizes certain U.S. federal income tax consequences of
investing in the Fund. Before investing, you should consult your own tax
adviser for more information concerning the federal, foreign, state and local
tax consequences of investing in, redeeming or exchanging Fund shares.

-14-
<PAGE>

APPENDIX A

DESCRIPTION OF BOND RATINGS ASSIGNED BY
STANDARD & POOR'S AND
MOODY'S INVESTORS SERVICE, INC.

STANDARD & POOR'S
- -----------------

AAA

This is the highest rating assigned by Standard & Poor's to a debt obligation
and indicates an extremely strong capacity to pay interest and repay principal.

BBB

BB, B, CCC, CC

The rating C is reserved for income bonds on which no interest is being paid.

Bonds rated D are in default, and payment of interest and/or repayment of
principal is in arrears.

This symbol is attached to the ratings of instruments with significant noncredit
risks such as risks to principal or volatility of expected returns.

Plus (+) or Minus (-): The ratings from "AA" to "B" may be modified by the
addition of a plus or minus sign to show relative standing within the major
rating categories.

A-1
<PAGE>

MOODY'S INVESTORS SERVICE, INC.
- -------------------------------

AAA

BAA

CAA

Bonds which are rated Caa are of poor standing. Such issues may be in default
or there may be present elements of danger with respect to principal or
interest.

Bonds which are rated Ca represent obligations which are speculative in a high
degree. Such issues are often in default or have other marked shortcomings.

A-2
<PAGE>

Bonds which are rated C are the lowest rated class of bonds, and issues so rated
can be regarded as having extremely poor prospects of ever attaining any real
investment standing.

Should no rating be assigned by Moody's, the reason may be one of the following:

1. An application for rating was not received or accepted.

2. The issue or issuer belongs to a group of securities that are not
rated as a matter of policy.

3. There is lack of essential data pertaining to the issue or issuer.

4. The issue was privately placed in which case the rating is not
published in Moody's publications.

A-3
<PAGE>

LOOMIS SAYLES INVESTMENT TRUST

LOOMIS SAYLES CALIFORNIA TAX-FREE INCOME FUND

STATEMENT OF ADDITIONAL INFORMATION

April 22, 1998

This Statement of Additional Information is not a prospectus. This Statement of
Additional Information relates to the Prospectus (the "Prospectus") of Loomis
Sayles California Tax-Free Income Fund, a series of Loomis Sayles Investment
Trust, dated April 22, 1998, and should be read in conjunction therewith. A
copy of the Prospectus may be obtained from Loomis Sayles Investment Trust, One
Financial Center, Boston, Massachusetts 02111.
<PAGE>

<TABLE>
<CAPTION>
TABLE OF CONTENTS
<S> <C>
INVESTMENT OBJECTIVE, POLICIES AND RESTRICTIONS...................... -3-

MANAGEMENT OF THE TRUST.............................................. -10-

INVESTMENT ADVISORY AND OTHER SERVICES............................... -13-

PORTFOLIO TRANSACTIONS AND BROKERAGE................................. -15-

DESCRIPTION OF THE TRUST............................................. -16-

HOW TO BUY SHARES.................................................... -19-

NET ASSET VALUE...................................................... -19-

REDEMPTIONS.......................................................... -19-

INCOME DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAX STATUS.......... -20-

FINANCIAL STATEMENTS................................................. -23-

CALCULATION OF YIELD AND TOTAL RETURN................................ -23-

PERFORMANCE COMPARISONS.............................................. -24-

PERFORMANCE DATA..................................................... -28-

APPENDIX APUBLICATIONS THAT MAY CONTAIN FUND INFORMATION............. -29-

APPENDIX BADVERTISING AND PROMOTIONAL LITERATURE..................... -31-
</TABLE>

2
<PAGE>

INVESTMENT OBJECTIVE, POLICIES AND RESTRICTIONS

The investment objective and policies of the Loomis Sayles California Tax-
Free Income Fund (the "Fund"), a series of Loomis Sayles Investment Trust (the
"Trust"), are summarized in the Prospectus under "Investment Objective and
Policies" and "More Information About the Fund's Investments." The investment
policies of the Fund set forth in the Prospectus and in this Statement of
Additional Information may be changed by Loomis, Sayles & Company, L.P. ("Loomis
Sayles"), the Fund's investment adviser, subject to review and approval by the
Trust's board of trustees (the "Trustees"), without shareholder approval except
that the investment objective of the Fund as set forth in the Prospectus and any
Fund policy explicitly identified as "fundamental" may not be changed without
the approval of the holders of a majority of the outstanding shares of the Fund
(which means the lesser of (i) 67% of the shares of the Fund represented at a
meeting at which at least 50% of the outstanding shares are represented or (ii)
more than 50% of the outstanding shares).

In addition to its investment objective and policies set forth in the
Prospectus, the following investment restrictions are policies of the Fund (and
those marked with an asterisk are fundamental policies of the Fund):

The Fund will not:

*(1) Act as underwriter, except to the extent that, in connection with the
disposition of portfolio securities, it may be deemed to be an
underwriter under certain federal securities laws.

*(2) Invest in oil, gas or other mineral leases, rights or royalty
contracts or in real estate, commodities or commodity contracts. (This
restriction does not prevent the Fund from investing in issuers that
invest or deal in the foregoing types of assets or from purchasing
securities that are secured by real estate.)

*(3) Make loans. (For purposes of this investment restriction, neither (i)
entering into repurchase agreements nor (ii) purchasing bonds,
debentures, commercial paper, corporate notes and similar evidences of
indebtedness, which are a part of an issue to the public, is
considered the making of a loan.)

*(4) Change its classification pursuant to Section 5(b) of the Investment
Company Act of 1940, as amended (the "1940 Act"), from a "diversified"
to "non-diversified" management investment company.

*(5) Purchase any security if, as a result, more than 25% of the Fund's
total assets (taken at current value) would be invested in any one
industry (for purposes of this restriction, governmental issuers of
tax-exempt securities are not considered part of any industry).

3
<PAGE>

use of reverse repurchase agreements and "dollar roll" arrangements
shall not constitute borrowing by the Fund for purposes of this
restriction.

*(7) Purchase any illiquid security, including any security that is not
readily marketable, if, as a result, more than 15% of the Fund's net
assets (based on current value) would then be invested in such
securities.

*(8) Issue senior securities other than any borrowing permitted by
restriction (6) above. (For the purposes of this restriction none of
the following is deemed to be a senior security: any pledge, mortgage,
hypothecation or other encumbrance of assets; any collateral
arrangements with respect to options, futures contracts and options on
futures contracts and with respect to initial and variation margin;
and the purchase or sale of or entry into options, forward contracts,
futures contracts, options on futures contracts, swap contracts or any
other derivative investments to the extent that Loomis Sayles
determines that the Fund is not required to treat such investments as
senior securities pursuant to the pronouncements of the Securities and
Exchange Commission (the "SEC") or its staff.)

The Fund intends, based on the views of the staff of the SEC, to restrict
its investments, if any, in repurchase agreements maturing in more than seven
days, together with other investments in illiquid securities, to the percentage
permitted by restriction (7) above.

Although authorized to invest in restricted securities, the Fund, as a
matter of non-fundamental operating policy, currently does not intend to invest
in such securities, except Rule 144A securities.

Portfolio Turnover
- ------------------

Portfolio turnover considerations will not limit Loomis Sayles's investment
discretion in managing the Fund's assets. The Fund anticipates that its
portfolio turnover rates will vary significantly from time to time depending on
the volatility of economic and market conditions. High portfolio turnover rates
may result in higher costs such as higher brokerage commissions and higher
levels of taxable gain. See "Portfolio Transactions and Brokerage" for a
description of Loomis Sayles's brokerage practices and "Income Dividends,
Capital Gain Distributions and Tax Status" for more information about the tax
consequences of investing in the Fund.

When-Issued Securities
- ----------------------

4
<PAGE>

make commitments to purchase on a when-issued or delayed-delivery basis only
securities meeting the Fund's investment criteria. The Fund may take delivery
of these securities or, if it is deemed advisable as a matter of investment
strategy, the Fund may sell these securities before the settlement date. When
the time comes to pay for when-issued or delayed-delivery securities, the Fund
will meet its obligations from then available cash flow or the sale of
securities, or from the sale of the when-issued or delayed-delivery securities
themselves (which may have a value greater or less than the Fund's payment
obligation).

U.S. Government Securities
- --------------------------

U.S. Government Securities include direct obligations of the U.S. Treasury,
as well as securities issued or guaranteed by U.S. Government agencies,
authorities and instrumentalities, including, among others, the Government
National Mortgage Association, the Federal Home Loan Mortgage Corporation, the
Federal National Mortgage Association, the Federal Housing Administration, the
Resolution Funding Corporation, the Federal Farm Credit Banks, the Federal Home
Loan Bank, the Tennessee Valley Authority, the Student Loan Marketing
Association and the Small Business Administration. More detailed information
about some of these categories of U.S. Government Securities follows.

. U.S. Treasury Bills - Direct obligations of the U.S. Treasury which
-------------------
are issued in maturities of one year or less. No interest is paid on Treasury
bills; instead, they are issued at a discount and repaid at full face value when
they mature. They are backed by the full faith and credit of the U.S.
Government.

. U.S. Treasury Notes and Bonds - Direct obligations of the U.S.
-----------------------------
Treasury issued in maturities that vary between one and forty years, with
interest normally payable every six months. They are backed by the full faith
and credit of the U.S. Government.

. "Ginnie Maes" - Debt securities issued by a mortgage banker or other
-------------
mortgagee which represent interests in a pool of mortgages insured by the
Federal Housing Administration or the Farmer's Home Administration or guaranteed
by the Veterans Administration. The Government National Mortgage Association
("GNMA") guarantees the timely payment of principal and interest when such
payments are due, whether or not these amounts are collected by the issuer of
these certificates on the underlying mortgages. An assistant attorney general
of the United States has rendered an opinion that the guarantee by GNMA is a
general obligation of the United States backed by its full faith and credit.
Mortgages included in single family or multi-family residential mortgage pools
backing an issue of Ginnie Maes have a maximum maturity of up to 30 years.
Scheduled payments of principal and interest are made to the registered holders
of Ginnie Maes (such as the Fund) each month. Unscheduled prepayments may be
made by homeowners, or as a result of a default. Prepayments are passed through
to the registered holder of Ginnie Maes along with regular monthly payments of
principal and interest.

5
<PAGE>

by FNMA that are guaranteed as to timely payment of principal and interest by
FNMA but are not backed by the full faith and credit of the U.S. Government.

. "Freddie Macs" - The Federal Home Loan Mortgage Corporation ("FHLMC")
--------------
is a corporate instrumentality of the U.S. Government. Freddie Macs are
participation certificates issued by FHLMC that represent an interest in
residential mortgages from FHLMC's National Portfolio. FHLMC guarantees the
timely payment of interest and ultimate collection of principal, but Freddie
Macs are not backed by the full faith and credit of the U.S. Government.

As described in the Prospectus, U.S. Government Securities generally do not
involve the credit risks associated with investments in other types of fixed
income securities, although, as a result, the yields available from U.S.
Government Securities are generally lower than the yields available from
corporate fixed income securities. Like other fixed income securities, however,
the values of U.S. Government Securities change as interest rates fluctuate.
Fluctuations in the value of portfolio securities will not affect interest
income on existing portfolio securities but will be reflected in the Fund's net
asset value.

Zero Coupon Bonds
- -----------------

Zero coupon bonds are debt obligations that do not entitle the holder to
any periodic payments of interest either for the entire life of the obligations
or for an initial period after the issuance of the obligations. Such bonds are
issued and traded at discounts from their face amounts. The amount of the
discount varies depending on such factors as the time remaining until maturity
of the bonds, prevailing interest rates, the liquidity of the security and the
perceived credit quality of the issuer. The market prices of zero coupon bonds
generally are more volatile than the market prices of securities that pay
interest periodically and are likely to respond to changes in interest rates to
a greater degree than do non-zero coupon bonds having similar maturities and
credit quality. In order to satisfy a requirement for qualification as a
"regulated investment company" under the Internal Revenue Code (the "Code"), the
Fund must distribute each year at least 90% of its net investment income,
including the original issue discount accrued on zero coupon bonds. Because an
investor investing in zero coupon bonds will not on a current basis receive cash
payments from the issuer in respect of accrued original issue discount, the Fund
may have to distribute cash obtained from other sources in order to satisfy the
90% distribution requirement under the Code. Such cash might be obtained from
selling other portfolio holdings of the Fund. In some circumstances, such sales
might be necessary in order to satisfy cash distribution requirements even
though investment considerations might otherwise make it undesirable for the
Fund to sell such securities at such time.

California Tax-Exempt Securities
- --------------------------------

In addition to general economic pressures, certain California
constitutional amendments, legislative measures, executive orders,
administrative regulations and voter initiatives could adversely affect the
State of California's ability to raise revenues to meet its financial
obligations. The following information is only a brief summary, is not a
complete description and is based on information drawn from official statements
and prospectuses relating to securities offerings of the State of California
that have come to the attention of the Trust and were available before the date
of

6
<PAGE>

this Statement of Additional Information. The Trust has not independently
verified the accuracy and completeness of the information contained in those
statements and prospectuses.

As used below, "California Tax-Exempt Securities" includes issues secured
by a direct payment obligation of the State and obligations of other issuers
that rely in whole or in part on State revenues to pay their obligations.
Property tax revenues and part of the State's General Fund surplus are
distributed to counties, cities and their various taxing entities; whether and
to what extent a portion of the State's General Fund will be so distributed in
the future is unclear.

Overview. After suffering through a severe recession, since the start of
--------
1994 California's economy has been on a steady recovery. The recession seriously
affected State tax revenues and caused an increase in expenditures for health
and welfare programs. As a result, from the late 1980s until 1992-93, the State
experienced recurring budget deficits. During this period, expenditures
exceeded revenues in four out of six years up to 1992-93, and the State
accumulated a budget deficit of about $2.8 billion at its peak at June 30, 1993.
A further consequence of the large budget imbalances was to significantly reduce
the State's available cash resources and require it to use a series of external
borrowings to meet its cash needs.

The State's financial condition improved markedly during the 1995-96 and
1996-97 fiscal years, through a combination of higher than expected revenues and
a slowdown in spending. The State's cash position also improved, and no
external borrowings occurred over the end of those two fiscal years. The
substantially greater tax revenues that the State received were spent largely on
schools (as mandated by State law), and the accumulated budget deficit was
finally eliminated. In January 1998, the State Department of Finance reported
that the State's budget reserve was $461 million as of June 30, 1997, and
projected that the budget reserve balance will be $329 million at June 30, 1998.
The Governor's proposed budget for 1998-99, which was released on January 9,
1998, projects that the budget reserve at June 30, 1999 will be $296
million.

Because of the deterioration in the State's financial condition, the
State's credit ratings have been reduced. Since October 1992, three major
nationally recognized statistical rating organizations

7
<PAGE>

have lowered the State's general obligation bond rating from the highest rating
of "AAA" to "A+" by Standard and Poor's, "A1" by Moody's Investors Service,
Inc., and "AA-" by Fitch Investors Service, Inc. In October 1997, Fitch
Investors Service, Inc. upgraded the State's general obligation bond rating from
"A+" to "AA-."

State Appropriations Limit. Subject to certain exceptions, the State is
--------------------------
subject to an annual appropriations limit imposed by its Constitution on
"proceeds of taxes." Various expenditures, including but not limited to debt
service on certain bonds and appropriations for qualified capital outlay
projects, are not included in the appropriations limit.

Issues Affecting Local Governments and Special Districts
- --------------------------------------------------------

Proposition 13. Certain California Tax-Exempt Securities may be
--------------
obligations of issuers that rely in whole or in part on ad valorem real property
taxes for revenue. In 1978, California voters approved Proposition 13, which
limits ad valorem real property taxes and restricts the ability of taxing
entities to increase property tax and other revenues. With certain exceptions,
the maximum ad valorem real property tax is limited to 1% of the value of real
property. The value of real property may be adjusted annually for inflation at a
rate not exceeding 2% per year, or reduced to reflect declining value, and may
also be adjusted when there is a change in ownership or new construction with
respect to the property. Constitutional challenges to Proposition 13 to date
have been unsuccessful.

The State, in response to the significant reduction in local property tax
revenues as a result of the passage of Proposition 13, enacted legislation to
provide local government with increased expenditures from the General Fund.
This post-Proposition 13 fiscal relief has ended.

Proposition 62. This initiative placed further restrictions on the ability
--------------
of local governments to raise taxes and allocate approved tax revenues. Although
some of the California Courts of Appeal held that parts of Proposition 62 were
unconstitutional, the California Supreme Court recently upheld Proposition 62's
requirement that special taxes be approved by a two-thirds vote of the voters
voting in an election on the issue. This decision may invalidate other taxes
that have been imposed by local governments in California and make it more
difficult for local governments to raise taxes.

Proposition 218. Passed in November 1996, this initiative places
---------------
additional limitations on the ability of California local governments to impose
or raise various taxes, assessments, charges and fees by requiring voter
approval of such items. General taxes and many assessments and fees that were
passed without public approval after 1994 and before November 6, 1996 must be
approved by voters to continue in effect. In addition, Proposition 218
clarified the right of local voters to reduce taxes, fees, assessments or
charges. Proposition 218 does not affect the State's ability to levy or collect
taxes.

Propositions 98 and 111. These initiatives changed the State
-----------------------
appropriations limit and State funding of public education below the university
level by guaranteeing K-14 schools a minimum share of General Fund revenues.
The initiatives also require that the State establish a prudent reserve fund for
public education.

8
<PAGE>

Appropriations Limit. Local governmental entities are also subject to
--------------------
annual appropriations limits. If a local government's revenues in any year
exceed the limit, the excess must be returned to the public through a revision
of tax rates or fee schedules over the following two years.

Conclusion. The effect of these Constitutional and statutory changes and
----------
of budget developments on the ability of California issuers to pay interest and
principal on their obligations remains unclear, and may depend upon whether a
particular bond is a general obligation or limited obligation bond (limited
obligation bonds being generally less affected). There is no assurance that any
California issuer will make full or timely payments of principal or interest or
remain solvent. For example, in December 1994, Orange County filed for
bankruptcy.

Additional Issues.
- -----------------

Mortgages and Deeds of Trust. The Fund may invest in issues that are
----------------------------
secured in whole or in part by mortgages or deeds of trust on real property.
California law limits the remedies of a creditor secured by a mortgage or a deed
of trust, which may result in delays in the flow of revenues to, and debt
service paid by, an issuer.

Lease Financings. Some local governments and districts finance certain
----------------
activities through lease arrangements. It is uncertain whether such lease
financings are debt that requires voter approval.

Seismic Risk. It is impossible to predict the time, location or magnitude
------------
of a major earthquake or its effect on the California economy. In January 1994
a major earthquake struck Los Angeles, causing significant damage to structures
and facilities in a four-county area. The possibility exists that another such
earthquake could create a major dislocation of the California economy.

Rule 144A Securities
- --------------------

The Fund may purchase Rule 144A securities. These are privately offered
securities that can be resold only to certain qualified institutional buyers.
Rule 144A securities are treated as illiquid, unless Loomis Sayles has
determined, under guidelines established by the Trustees, that a particular
issue of Rule 144A securities is liquid. Under the guidelines, Loomis Sayles
considers such factors as: (1) the frequency of trades and quotes for a
security; (2) the number of dealers willing to purchase or sell the security and
the number of other potential purchasers; (3) dealer undertakings to make a
market in the security; and (4) the nature of the security and the nature of
marketplace trades therefor.

9
<PAGE>

MANAGEMENT OF THE TRUST

The trustee and officers of the Trust and their principal occupations
during the past five years are as follows:

TIMOTHY J. HUNT (66) -- Trustee. 26 Dennett Road, Marblehead, Massachusetts.
-------
Retired. Formerly, Vice President and Director of Fixed Income Research,
Loomis Sayles.

DANIEL J. FUSS (64) -- President. Executive Vice President and Director, Loomis
---------
Sayles.

MARK W. HOLLAND (48) -- Treasurer. Vice President-Finance and Administration
---------
and Director, Loomis Sayles.

SHEILA M. BARRY (52) -- Secretary and Compliance Officer. Assistant General
--------------------------------
Counsel and Vice President, Loomis Sayles. Formerly, Senior Counsel and
Vice President, New England Funds, L.P.

ROBERT J. BLANDING (50) -- Executive Vice President. 465 First Street West,
------------------------
Sonoma, California. President, Chairman, Director and Chief Executive
Officer, Loomis Sayles.

WILLIAM F. CAMP (36) -- Vice President. 1533 North Woodward, Bloomfield Hills,
--------------
Michigan. Vice President, Loomis Sayles. Formerly, Portfolio Manager,
Kmart Corporation.

QUENTIN P. FAULKNER (59) -- Vice President. Vice President, Loomis Sayles.
--------------

KATHLEEN C. GAFFNEY (36) -- Vice President. Vice President, Loomis Sayles.
--------------

JEFFREY L. MEADE (47) -- Vice President. Chief Operating Officer, Executive
--------------
Vice President and Director, Loomis Sayles.

ROBERT K. PAYNE (55) -- Vice President. 555 California Street, San Francisco,
--------------
California. Vice President, Loomis Sayles.

ANTHONY J. WILKINS (56) -- Vice President. Vice President and Director, Loomis
--------------
Sayles.

MARI J. SUGAHARA (33) -- Vice President. Vice President, Loomis Sayles.
---------------

10
<PAGE>

FREDERICK E. SWEENEY, JR. (37) --Vice President. Vice President, Loomis Sayles.
---------------
Formerly, served as an Investment Consultant at Meketa Investment Group and
prior to that served as Vice President of New England Investment
Associates.

JOHN F. YEAGER (34) -- Vice President. Vice President, Loomis Sayles.
--------------
Formerly, Vice President-Marketing, INVESCO Funds Group and Assistant
Comptroller, INVESCO Capital Management.

Previous positions during the past five years with Loomis Sayles are
omitted, if not materially different from the positions listed. Except as
indicated above, the address of each officer of the Trust affiliated with Loomis
Sayles is One Financial Center, Boston, Massachusetts 02111.

The Trust pays no compensation to its officers listed above who are
interested persons of the Trust. Each Trustee who is not affiliated with Loomis
Sayles is compensated at the rate of $10,000 per annum. No Trustee will receive
compensation from any other investment company which is advised by Loomis Sayles
or its affiliates or which holds itself out to investors as being related to the
Trust.

<TABLE>
<CAPTION>
COMPENSATION TABLE
for the year ended December 31, 1997

- ------------------------------------------------------------------------------------------------
<S> <C> <C> <C> <C>
(1) (2) (3) (4) (5)

Name of Person, Aggregate Pension or Estimated Total Compensation
Position Compensation Retirement Annual from Trust and Fund
from Trust Benefits Benefits Upon Complex Paid to
Accrued as Part Retirement Trustee
of Fund Expenses
- ------------------------------------------------------------------------------------------------

Timothy J. Hunt, $10,000 $0 $0 $10,000
Trustee
</TABLE>

As of the date hereof, the Trustee and officers as a group owned less than
1% of the outstanding shares of the Fund.

The following table sets forth the name, address and percentage ownership
of each holder of 5% or more of the Fund's outstanding voting securities as of
March 31, 1998.

<TABLE>
<CAPTION>
Shareholder Address Percentage of Shares Held
- ----------- ------- -------------------------
<S> <C> <C>
</TABLE>

11
<PAGE>

<TABLE>
<S> <C> <C>
First American 400 First American Center 11.84%
Trust Company, Paul M. Nashville, TN 37237-0402
Davis for Peter Davis

Phillipa Scott Trust 16133 Ventura Boulevard 9.73%
Encino, CA 91436

Koeppel Family Trust 1445 Cabellero Road 8.68%
Arcadia, CA 91006

Joseph E. & Ellen Mueth 225 S. Lake Avenue 8.56%
TTEEs, Mueth Family Trust Pasadena, CA 91101

Camille Basha & Connie 1015 San Marino Avenue 7.76%
Vitale JTTE San Marino, CA 91108

Judith Ann Kenyon, Trustee 1755 Warwick Avenue 6.00%
Trust Dated 2/23/89 San Marino, CA 91108

Connie Vitale & Camille 1015 San Marino Avenue 5.74%
Basha JTTE San Marino, CA 91108

First American 400 First American Center 5.22%
Trust Company, Nashville, TN 37237-0402
Paul Davis for Peter Davis
Family
</TABLE>

12
<PAGE>

INVESTMENT ADVISORY AND OTHER SERVICES

Advisory Agreement. Loomis Sayles serves as investment adviser to the
------------------
Fund under an advisory agreement with the Trust dated August 30, 1996. Under
the advisory agreement, Loomis Sayles manages the investment and reinvestment of
the assets of the Fund and generally administers its affairs, subject to
supervision by the Trustees. Loomis Sayles furnishes, at its own expense, all
necessary office space, office supplies, facilities and equipment, services of
executive and other personnel of the Fund and certain administrative services.
For these services, the advisory agreement provides that the Fund shall pay
Loomis Sayles a monthly investment advisory fee at the annual rate of .50% of
the Fund's average weekly net assets.

Under the advisory agreement, if the total ordinary business expenses of
the Fund or the Trust as a whole for any fiscal year exceed the lowest
applicable limitation (based on percentage of average net assets or income)
prescribed by any state in which the shares of the Fund or the Trust are
qualified for sale, Loomis Sayles shall pay such excess.

As described in the Prospectus, Loomis Sayles has voluntarily undertaken
for an indefinite period to limit the Fund's total operating expenses. These
arrangements may be modified or terminated by Loomis Sayles at any time, subject
to prior notice to shareholders.

During the 1995 fiscal period (June 1, 1995 through December 31, 1995),
the 1996, and the 1997 fiscal years, Loomis Sayles received the following
amounts of investment advisory fees from the Fund (before voluntary fee
reductions and expense assumptions) and waived and reimbursed the following
amounts of fees for the Fund:

<TABLE>
<CAPTION>
Period
Waivers/Reimbursements Advisory Fees Fee
- ---------------------- ------------- ---
<S> <C> <C>
1995 $19,742 $ 28,897
1996 $52,945 $ 64,804
1997 $77,450 $117,260
</TABLE>

The advisory agreement provides that it will continue in effect for two
years from its date of execution and thereafter from year to year if its
continuance is approved at least annually (i) by the Trustees or by vote of a
majority of the outstanding voting securities of the Fund and (ii) by vote of a
majority of the Trustees who are not "interested persons" of the Trust or Loomis
Sayles, as that term is defined in the 1940 Act, cast in person at a meeting
called for the purpose of voting on such approval. Any amendment to the advisory
agreement must be approved by vote of a majority of the outstanding voting
securities of the Fund and by vote of a majority of the Trustees who are not
interested persons, cast in person at a meeting called for the purpose of voting
on such approval.

13
<PAGE>

agreement will automatically terminate if the Trust or the Fund shall at any
time be required by Loomis Sayles to eliminate all reference to the words
"Loomis" or "Sayles" in the name of the Trust or the Fund, unless the
continuance of the agreement after such change of name is approved by a majority
of the outstanding voting securities of the Fund and by a majority of the
Trustees who are not interested persons of the Trust or Loomis Sayles, cast in
person at a meeting called for the purpose of voting on such approval.

The advisory agreement provides that Loomis Sayles shall not be subject to
any liability in connection with the performance of its services thereunder in
the absence of willful misfeasance, bad faith, gross negligence or reckless
disregard of its obligations and duties.

Loomis Sayles acts as investment adviser to the seventeen series of the
Loomis Sayles Funds, each a series of a registered open-end diversified
management investment company. Loomis Sayles acts as investment adviser or sub-
adviser to New England Star Advisers Funds, New England Value Fund, New England
Balanced Fund and New England Strategic Income Fund, which are series of New
England Funds Trust I, a registered open-end management investment company, New
England High Income Fund, a series of New England Funds Trust II, a registered
open-end management investment company, New England Equity Income Fund, a series
of New England Funds Trust III, a registered open-end management investment
company and to the Balanced Series and the Small Cap Series of New England
Zenith Funds, which is also a registered open-end management investment company.
Loomis Sayles also provides investment advice to numerous other corporate and
fiduciary clients.

The general partner of Loomis Sayles is a special purpose corporation
that is an indirect wholly-owned subsidiary of Nvest Companies, L.P. ("Nvest
Companies"). Nvest Companies' managing general partner, Nvest Corporation, is a
direct wholly-owned subsidiary of Metropolitan Life Insurance Company ("Met
Life"), a mutual life insurance company. Nvest Companies' advising general
partner, Nvest, L.P., is a publicly traded company listed on the New York Stock
Exchange. Nvest Corporation is the sole general partner of Nvest L.P.

Officers of the Trust who hold positions with Loomis Sayles are listed
under "Management of the Trust" in this Statement of Additional Information.
Certain officers of the Trust also serve as officers, directors and trustees of
other investment companies and clients advised by Loomis Sayles. The other
investment companies and clients sometimes invest in securities in which the
Fund also invests. If the Fund and such other investment companies or clients
desire to buy or sell the same portfolio securities at the same time, purchases
and sales may be allocated, to the extent practicable, on a pro rata basis in
proportion to the amounts desired to be purchased or sold for each. It is
recognized that in some cases the practices described in this paragraph could
have a detrimental effect on the price or amount of the securities which the
Fund purchases or sells. In other cases, however, it is believed that these
practices may benefit the Fund. It is the opinion of the Trustee

14
<PAGE>

that the desirability of retaining Loomis Sayles as investment adviser for the
Fund outweighs the disadvantages, if any, which might result from these
practices.

Custodial Arrangements. State Street Bank and Trust Company ("State
----------------------
Street"), Boston, Massachusetts 02102, is the Trust's custodian. As such, State
Street holds in safekeeping certificated securities and cash belonging to the
Fund and, in such capacity, is the registered owner of securities held in book
entry form belonging to the Fund. Upon instruction, State Street receives and
delivers cash and securities of the Fund in connection with Fund transactions
and collects all dividends and other distributions made with respect to Fund
portfolio securities. State Street also maintains certain accounts and records
of the Fund and calculates the total net asset value, total net income and net
asset value per share of the Fund on a daily basis.

Independent Accountants. The Fund's independent accountants are Coopers &
-----------------------
Lybrand L.L.P. ("Coopers & Lybrand"), One Post Office Square, Boston,
Massachusetts 02109. Coopers & Lybrand conducts an annual audit of the Trust's
financial statements and financial highlights, assists in the preparation of the
Fund's federal and state income tax returns and consults with the Fund as to
matters of accounting and federal and state income taxation.

PORTFOLIO TRANSACTIONS AND BROKERAGE

In placing orders for the purchase and sale of portfolio securities for
the Fund, Loomis Sayles always seeks the best price and execution. Transactions
are carried out through broker-dealers who make the primary market for
securities unless, in the judgment of Loomis Sayles, a more favorable price can
be obtained by carrying out such transactions through other brokers or dealers.

Loomis Sayles selects only brokers or dealers which it believes are
financially responsible, will provide efficient and effective services in
executing, clearing and settling an order and will charge commission rates
which, when combined with the quality of the foregoing services, will produce
the best price and execution for the transaction. This does not necessarily
mean that the lowest available brokerage commission will be paid for a
transaction. However, the Fund will only pay commissions that Loomis Sayles
believes to be competitive with generally prevailing rates. Loomis Sayles will
use its best efforts to obtain information as to the general level of commission
rates being charged by the brokerage community from time to time and will
evaluate the overall reasonableness of brokerage commissions paid on
transactions by reference to such data. In making such evaluation, all factors
affecting liquidity and execution of the order, as well as the amount of the
capital commitment by the broker in connection with the order, are taken into
account. The Fund will not pay a broker a commission at a higher rate than
otherwise available for the same transaction in recognition of the value of
research services provided by the broker or in recognition of the value of any
other services provided by the broker which do not contribute to the best price
and execution of the transaction.

15
<PAGE>

structure, but also meetings with management representatives of issuers and with
other analysts and specialists. Although it is not possible to assign an exact
dollar value to these services, they may, to the extent used, tend to reduce
Loomis Sayles's expenses. Such services may be used by Loomis Sayles in
servicing other client accounts and in some cases may not be used with respect
to the Fund. Receipt of services or products other than research from brokers is
not a factor in the selection of brokers.

The following table sets forth for the 1995 fiscal period (June 1, 1995 to
December 31, 1995), the 1996 and the 1997 fiscal years (1) the aggregate dollar
amounts of brokerage commissions paid on portfolio transactions during such
periods, (2) the dollar amounts of transactions on which commissions were paid
during such periods that were directed to brokers providing research services
("directed transactions") and (3) the dollar amounts of commissions paid on
directed transactions during such periods:

<TABLE>
<CAPTION>
(1) (2) (3)
Aggregate Commissions
Brokerage Directed On Directed
Commissions Transactions Transactions
Period ($) ($) ($)
------ ----------- ------------ ------------
<S> <C> <C> <C>
1995 $ 0 $ 0 $ 0
1996 $ 0 $ 0 $ 0
1997 $ 0 $ 0 $ 0
</TABLE>

DESCRIPTION OF THE TRUST

The Trust, registered with the SEC as a diversified open-end management
investment company, is organized as a Massachusetts business trust under the
laws of The Commonwealth of Massachusetts by an Agreement and Declaration of
Trust (the "Declaration of Trust") dated December 23, 1993.

The Declaration of Trust currently permits the Trustees to issue an
unlimited number of full and fractional shares of each series. Each share of
the Fund represents an equal proportionate interest in the Fund with each other
share of the Fund and is entitled to a proportionate interest in the dividends
and distributions from the Fund. The shares of the Fund do not have any
preemptive rights. Upon termination of the Fund, whether pursuant to
liquidation of the Trust or otherwise, shareholders of the Fund are entitled to
share pro rata in the net assets of the Fund available for distribution to
shareholders. The Declaration of Trust also permits the Trustees to charge
shareholders directly for custodial, transfer agency and servicing expenses.

16
<PAGE>

of the Trust are allocated by or under the direction of the Trustees in such
manner as the Trustees determine to be fair and equitable. While the expenses of
the Trust are allocated to the separate books of account of the Fund, certain
expenses may be legally chargeable against the assets of all series.

The Declaration of Trust also permits the Trustees, without shareholder
approval, to issue shares of the Trust in one or more series, and to subdivide
any series of shares into various classes of shares with such dividend
preferences and other rights as the Trustees may designate. While the Trustees
have no current intention to subdivide any series of shares into classes, this
flexibility is intended to allow them to provide for an equitable allocation of
the impact of any future regulatory requirements which might affect various
classes of shareholders differently, or to permit shares of a series to be
distributed through more than one distribution channel, with the costs of the
particular means of distribution (or costs of related services) to be borne by
the shareholders who purchase through that means of distribution. The Trustees
may also, without shareholder approval, establish one or more additional
separate portfolios for investments in the Trust or merge two or more existing
portfolios. Shareholders' investments in such an additional or merged portfolio
would be evidenced by a separate series of shares (i.e., a new "fund").

The Declaration of Trust provides for the perpetual existence of the
Trust. The Trust or the Fund, however, may be terminated at any time by vote of
at least two-thirds of the outstanding shares of the Trust or the Fund,
respectively. The Declaration of Trust further provides that the Trustees may
also terminate the Trust or the Fund upon written notice to the shareholders.
As a matter of policy, however, the Trustees will not terminate the Trust or the
Fund without submitting the matter to a vote of the shareholders of the Trust or
the Fund, respectively.

Voting Rights
- -------------

As summarized in the Prospectus, shareholders are entitled to one vote for
each full share held (with a fractional vote for each fractional share held) and
may vote (to the extent provided in the Declaration of Trust) in the election of
Trustees and the termination of the Trust and on other matters submitted to the
vote of shareholders.

The Declaration of Trust provides that on any matter submitted to a vote
of all Trust shareholders, all Trust shares entitled to vote shall be voted
together irrespective of series or sub-series unless the rights of a particular
series or sub-series would be adversely affected by the vote, in which case a
separate vote of that series or sub-series shall also be required to decide the
question. Also, a separate vote for each series or sub-series shall be held
whenever required by the 1940 Act or any rule thereunder. Rule 18f-2 under the
1940 Act provides in effect that a class shall be deemed to be affected by a
matter unless it is clear that the interests of each class in the matter are
substantially identical or that the matter does not affect any interest of such
class. On matters exclusively affecting an individual series, only shareholders
of that series are entitled to vote. Consistent with the current position of the
SEC, shareholders of all series vote together, irrespective of series, on the
election of Trustees and the selection of the Trust's independent accountants,
but shareholders of each series vote separately on other matters requiring
shareholder approval, such as certain changes in investment policies of that
series or the approval of the investment advisory agreement relating to that
series. Voting rights are not cumulative.

17
<PAGE>

There will normally be no meetings of shareholders for the purpose of
electing Trustees except that, in accordance with the 1940 Act, (i) the Trust
will hold a shareholders' meeting for the election of Trustees at such time as
less than a majority of the Trustees holding office have been elected by
shareholders, and (ii) if, as a result of a vacancy on the Board of Trustees,
less than two-thirds of the Trustees holding office have been elected by the
shareholders, that vacancy may be filled only by a vote of the shareholders. In
addition, Trustees may be removed from office by a written consent signed by the
holders of two-thirds of the outstanding shares and filed with the Trust's
custodian or by a vote of the holders of two-thirds of the outstanding shares at
a meeting duly called for that purpose, which meeting shall be held upon the
written request of the holders of not less than 10% of the outstanding shares.

Upon written request by the holders of shares having a net asset value
constituting 1% of the outstanding shares stating that such shareholders wish to
communicate with the other shareholders for the purpose of obtaining the
signatures necessary to demand a meeting to consider removal of a Trustee, the
Trust has undertaken to provide a list of shareholders or to disseminate
appropriate materials (at the expense of the requesting shareholders).

Except as set forth above, the Trustees shall continue to hold office and
may appoint successor Trustees.

No amendment may be made to the Declaration of Trust without the
affirmative vote of a majority of the outstanding shares of the Trust, except
(i) to change the Trust's name or to cure technical problems in the Declaration
of Trust, (ii) to establish, change or eliminate the par value of any shares
(currently all shares have no par value) and (iii) to issue shares of the Trust
in one or more series, and to subdivide any series of shares into various
classes of shares with such dividend preferences and other rights as the
Trustees may designate.

Shareholder and Trustee Liability
- ---------------------------------

Under Massachusetts law shareholders could, under certain circumstances,
be held personally liable for the obligations of the Fund. However, the
Declaration of Trust disclaims shareholder liability for acts or obligations of
each fund and requires that notice of such disclaimer be given in each
agreement, obligation or instrument entered into or executed by the Trust or the
Trustees. The Declaration of Trust provides for indemnification out of Fund
property for all loss and expense of any shareholder held personally liable for
the obligations of the Fund. Thus, the risk of a shareholder incurring
financial loss on account of shareholder liability is considered remote since it
is limited to circumstances in which the disclaimer is inoperative and the Fund
itself would be unable to meet its obligations.

18
<PAGE>

Trust. No officer or Trustee may be indemnified against any liability to the
Trust or the Trust's shareholders to which such person would otherwise be
subject by reason of willful misfeasance, bad faith, gross negligence or
reckless disregard of the duties involved in the conduct of his or her office.

HOW TO BUY SHARES

The procedures for purchasing shares of the Fund and for determining the
offering price of such shares are summarized in the Prospectus under "How to
Purchase Shares."

NET ASSET VALUE

The net asset value of the shares of the Fund is determined by dividing
the Fund's total net assets (the excess of its assets over its liabilities) by
the total number of shares of the Fund outstanding and rounding to the nearest
cent. Such determination is made at least weekly and as of the close of regular
trading on the New York Stock Exchange (the "Exchange") on any day on which an
order for purchase or redemption of the Fund's shares is received and on which
the Exchange is open for unrestricted trading. During the twelve months
following the date of this Statement of Additional Information, the Exchange is
expected to be closed on the following weekdays: Memorial Day as observed,
Independence Day, Labor Day, Thanksgiving Day, Christmas Day, New Year's Day,
Martin Luther King, Jr. Day, Presidents' Day and Good Friday. Long-term debt
securities are valued by a pricing service, which determines valuations of
normal institutional-size trading units of long-term debt securities. Such
valuations are determined using methods based on market transactions for
comparable securities and on various relationships among securities that are
generally recognized by institutional traders. Other securities for which
current market quotations are not readily available (including restricted
securities, if any) and all other assets are taken at fair value as determined
in good faith by the Trustees, although the actual calculations may be made by
persons acting pursuant to the direction of the Trustees.

REDEMPTIONS

The procedures for redemption of Fund shares are summarized in the
Prospectus under "How to Redeem Shares."

The redemption price will be the net asset value per share next determined
--------------------------------------------------------------------------
after the redemption request and any necessary special documentation are
- ------------------------------------------------------------------------
received by the Trust in proper form. Proceeds resulting from a written
- -------------------------------------
redemption request will normally be mailed to you within seven days after
receipt of your request in good order. In those cases where you have recently
purchased your shares by check and your check was received less than fifteen
days prior to the redemption request, the Fund may withhold redemption proceeds
until your check has cleared.

The Fund will normally redeem shares for cash; however, the Fund reserves
the right to pay the redemption price wholly or partly in kind if the Trustees
determine it to be advisable in the interest of the remaining shareholders. If
portfolio securities are distributed in lieu of cash, the shareholder will
normally incur brokerage commissions upon subsequent disposition of any such
securities.

19
<PAGE>

A redemption constitutes a sale of the shares for federal income tax
purposes on which the investor may realize a long- or short-term capital gain or
loss. See "Income Dividends, Capital Gain Distributions and Tax Status."

INCOME DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAX STATUS

As described in the Prospectus under "Dividends, Capital Gain
Distributions and Taxes" it is the policy of the Fund to pay its shareholders,
as monthly dividends, substantially all net income and to distribute annually
all net realized capital gains, if any, after offsetting any capital loss
carryovers.

Income dividends and capital gain distributions are payable in full and
fractional shares of the Fund based upon the net asset value determined as of
the close of regular trading on the Exchange on the record date for each
dividend or distribution. Shareholders, however, may elect to receive their
income dividends or capital gain distributions, or both, in cash. The election
may be made at any time by submitting a written request directly to the Trust.
In order for a change to be in effect for any dividend or distribution, it must
be received by the Trust on or before the record date for such dividend or
distribution.

As required by federal law, information concerning the federal tax status
of distributions from the Fund will be furnished to each shareholder for each
calendar year on or before January 31 of the succeeding year.

The Fund intends to qualify each year as a regulated investment company
under Subchapter M of the Code. In order so to qualify and to qualify for the
special tax treatment accorded regulated investment companies and their
shareholders, the Fund must, among other things, (i) derive at least 90% of its
gross income from dividends, interest, payments with respect to certain
securities loans, gains from the sale of securities or foreign currencies, or
other income derived with respect to its business of investing in such stock,
securities or currencies, (ii) distribute at least 90% of the sum of its taxable
net investment income, its tax-exempt income and the excess, if any, of net
short term capital gains over its net long-term capital losses for such year;
and (iii) at the end of each fiscal quarter hold at least 50% of the value of
its total assets in cash, government securities, securities of other regulated
investment companies, and other securities of issuers which represent, with
respect to each issuer, no more than 5% of the value of the Fund's total assets
and 10% of the outstanding voting securities of such issuer, and no more than
25% of the value of its total assets in the securities (other than those of the
U.S. government or other regulated investment companies) of any one issuer or of
two or more issuers which the Fund controls and which are engaged in the same,
similar or related trades and businesses. To the extent it qualifies for
treatment as a regulated investment company, the Fund will not be subject to
federal income tax on income paid to its shareholders in the form of dividends
or capital gain distributions.

An excise tax at the rate of 4% will be imposed on the excess, if any, of
the Fund's "required distribution" over its distributions in any calendar year.
Generally, the "required

20
<PAGE>

distribution" is 98% of the Fund's ordinary income for the calendar year plus
98% of its capital gain net income realized during the one-year period ending on
October 31 (or December 31, if the Fund is permitted to elect and so elects)
plus undistributed amounts from prior years. The Fund intends to make
distributions sufficient to avoid imposition of the excise tax. Distributions
declared by the Fund during October, November or December to shareholders of
record on a date in any such month and paid by the Fund during the following
January will be treated for federal tax purposes as paid by the Fund and
received by shareholders on December 31 of the year in which declared.

The Code permits a regulated investment company that at the close of each
quarter of the Funds taxable year has at least 50% of the value of its total
assets invested in obligations the interest on which is excludable from federal
gross income to pass through to its investors, tax-free, its net tax-exempt
interest income. The policy of the Fund is to pay each year as dividends all of
the Fund's tax-exempt interest income net of certain deductions. An exempt-
interest dividend is any dividend or part thereof derived from tax-exempt
interest and designated as an exempt-interest dividend in a written notice
mailed to shareholders after the close of the Fund's taxable year, but the
aggregate of such dividends may not exceed the net tax-exempt interest received
by the Fund during the taxable year. The percentage of the dividends paid for
any taxable year that qualifies as federal exempt-interest dividends will be the
same for all shareholders receiving dividends during such year, regardless of
the period for which the shares were held.

Exempt-interest dividends may be treated by shareholders as items of
interest excludable from their gross income under Section 103(a) of the Code but
may be taxable for federal alternative minimum tax purposes and for state and
local tax purposes. Each shareholder is advised to consult his or her tax
adviser with respect to whether exempt-interest dividends would retain the
exclusion under Section 103(a) if such shareholder were treated as a
"substantial user" or a "related person" to such user under Section 147(a) with
respect to facilities financed through any of the tax-exempt obligations held by
the Fund.

If, at the close of each quarter of its taxable year, at least 50% of the
value of the total assets of the Fund consists of obligations the interest on
which is exempt from California personal income taxation if held by an
individual, then the Fund will be qualified to pay dividends that are exempt
from California personal income tax. The Fund intends to qualify to pay such
dividends. For California personal income tax purposes, distributions derived
from other investments and distributions from any net realized capital gains
will be taxable, whether paid in cash or reinvested in additional shares.

Interest derived from California tax-exempt securities is not subject to
the California alternative minimum tax. For California personal income tax
purposes, the entire amount of interest on any indebtedness incurred to purchase
or carry shares of the Fund will not be deductible.

Distributions from investment income and capital gains, including
dividends derived from interest paid on California tax-exempt securities, will
be subject to California franchise tax and California corporate income tax.

21
<PAGE>

Shareholders of the Fund will be subject to federal income taxes on
taxable distributions made by the Fund whether received in cash or additional
shares of the Fund. Distributions by the Fund of net taxable income and short-
term capital gains, if any, will be taxable to shareholders as ordinary income.
Distributions of long-term capital gains, if any, will be taxable to
shareholders as long-term capital gains, without regard to how long a
shareholder has held shares of the Fund.

Taxable dividends and distributions on Fund shares received shortly after
their purchase, although economically a return of capital, are subject to
federal income taxes.

Redemptions and exchanges of the Fund's shares are taxable events and,
accordingly, shareholders may realize gains and losses on these transactions.
If shares have been held for more than one year, gain or loss realized will be
long-term capital gain or loss, provided the shareholder holds the shares as a
capital asset. In general, any long term gains realized upon a taxable
disposition of shares will be subject to a maximum tax rate of either 28% or 20%
depending on the shareholder's holding period in the Fund shares. If a
shareholder sells Fund shares held for six months or less at a loss, the loss
will be disallowed to the extent of any exempt-interest dividends received by
the shareholder with respect to the shares and will be treated as long-term
capital loss to the extent of any long-term capital gain distributions received
with respect to the shares. Furthermore, all or a portion of any loss will be
disallowed on the taxable disposition of Fund shares if the shareholder acquires
other shares of the Fund within 30 days before or after the disposition.

The Fund's investment in securities issued at a discount and certain other
obligations will (and investments in securities purchased at a discount may)
require the Fund to accrue and distribute income not yet received. In such
cases, the Fund may be required to sell assets (including when it is not
advantageous to do so) to generate the cash necessary to distribute as dividends
to its shareholders all of its income and gains and therefore to eliminate any
tax liability at the Fund level.

If the Fund engages in hedging transactions, including hedging
transactions in options, future contracts, and straddles, or other similar
transactions, it will be subject to special tax rules (including constructive
sale, mark-to market, straddle, wash sale, and short sale rules), the effect of
which may be to accelerate income to the Fund, defer losses to the Fund, cause
adjustments in the holding periods of the Fund's securities, or convert short-
term capital losses into long-term capital losses. These rules could therefore
affect the amount, timing and character of distributions to shareholders. The
Fund will endeavor to make any available elections pertaining to such
transactions in a manner believed to be in the best interests of the Fund.

22
<PAGE>

The foregoing is a general and abbreviated summary of the applicable
provisions of the Code, regulations and applicable provisions of California tax
law currently in effect. For the complete provisions, reference should be made
to the pertinent Code sections, regulations and applicable provisions of
California tax law. These authorities are subject to change by legislative or
administrative action.

Dividends and distributions also may be subject to other state and local
taxes or foreign taxes. Shareholders are urged to consult their tax advisers
regarding specific questions as to federal, foreign, state or local taxes.

The Internal Revenue Service recently revised its regulations affecting
the application to foreign investors of the back-up withholding and withholding
tax rules described above. The new regulations will generally be effective for
payments made on or after January 1, 1999 (although transition rules will
apply). In some circumstances, the new rules will increase the certification and
filing requirements imposed on foreign investors in order to qualify for
exemption from the 31% back-up withholding tax and for reduced withholding tax
rates under income tax treaties. Foreign investors in the Fund should consult
their tax advisors with respect to the potential application of these new
regulations.

FINANCIAL STATEMENTS

The Report of Independent Accountants, financial highlights and financial
statements of the Fund included in its 1997 Annual Report are incorporated
herein by reference to such Annual Report. Copies of such Annual Report are
available without charge upon request by writing Loomis Sayles, One Financial
Center, Boston, Massachusetts 02111 or telephoning (617) 482-2450.

The financial highlights included in the Prospectus under the headings
"Financial Highlights" and "Prior Performance" and incorporated by reference
into this Statement of Additional Information and the financial statements and
financial highlights contained in the Fund's 1997 Annual Report and incorporated
by reference into this Statement of Additional Information have both been
audited by Coopers & Lybrand L.L.P., independent accountants, and have been so
included and incorporated by reference in reliance upon the report of said firm,
which report is given upon their authority as experts in auditing and
accounting.

CALCULATION OF YIELD AND TOTAL RETURN

<PAGE>

income will reflect amortization of any market value premium or discount of
fixed income securities (except for obligations backed by mortgages or other
assets) and may include recognition of a pro rata portion of the stated dividend
rate of dividend paying portfolio securities. The Fund's yield will vary from
time to time depending upon market conditions, the composition of the Fund's
portfolio and operating expenses of the Trust allocated to the Fund. These
factors, and possible differences in the methods used in calculating yield,
should be considered when comparing the Fund's yield to yields published for
other investment companies and other investment vehicles. Yield should also be
considered relative to changes in the value of the Fund's shares and to the
relative risks associated with the investment objective and policies of the
Fund.

At any time in the future, yields may be higher or lower than past yields
and there can be no assurance that any historical results will continue.

Investors in the Fund are specifically advised that the net asset value
per share of the Fund may vary, just as yields for the Fund may vary. An
investor's focus on yield to the exclusion of the consideration of the value of
shares of the Fund may result in the investor's misunderstanding the total
return he or she may derive from the Fund.

Total Return. Total return with respect to the Fund is a measure of the
------------
change in value of an investment in the Fund over the period covered, and
assumes any dividends or capital gains distributions are reinvested immediately,
rather than paid to the investor in cash. The formula for total return used
herein includes four steps: (1) adding to the total number of shares purchased
through a hypothetical $1,000 investment in the Fund all additional shares which
would have been purchased if all dividends and distributions paid or distributed
during the period had been immediately reinvested; (2) calculating the value of
the hypothetical initial investment of $1,000 as of the end of the period by
multiplying the total number of shares owned at the end of the period by the net
asset value per share on the last trading day of the period; (3) assuming
redemption at the end of the period; and (4) dividing the resulting account
value by the initial $1,000 investment.

PERFORMANCE COMPARISONS

The Fund may from time to time include the yield and/or total return of
its shares in advertisements or information furnished to present or prospective
shareholders. The Fund may from time to time include in advertisements or
information furnished to present or prospective shareholders (i) the ranking of
performance figures relative to such figures for groups of mutual funds
categorized by Lipper Analytical Services, Inc. or Micropal, Inc. as having
similar investment objectives, (ii) the rating assigned to the Fund by
Morningstar, Inc. based on the Fund's risk-adjusted performance relative to
other mutual funds in its broad investment class, and/or (iii) the ranking of
performance figures relative to such figures for mutual funds in its general
investment category as determined by CDA/Weisenberger's Management Results.

LIPPER ANALYTICAL SERVICES, INC. distributes mutual fund rankings monthly.
--------------------------------
The rankings are based on total return performance calculated by Lipper,
generally reflecting changes in net asset value adjusted for reinvestment of
capital gains and income dividends. They do not reflect deduction of any sales
charges. Lipper rankings cover a variety of performance periods, including
year-to-date,

<PAGE>

1-year, 5-year, and 10-year performance. Lipper classifies mutual funds by
investment objective and asset category.

MICROPAL, INC. distributes mutual fund rankings weekly and monthly. The
--------------
rankings are based upon performance calculated by Micropal, generally reflecting
changes in net asset value that can be adjusted for the reinvestment of capital
gains and dividends. If deemed appropriate by the user, performance can also
reflect deductions for sales charges. Micropal rankings cover a variety of
performance periods, including year-to-date, 1-year, 5-year and 10-year
performance. Micropal classifies mutual funds by investment objective and asset
category.

MORNINGSTAR, INC. distributes mutual fund ratings twice a month. The
-----------------
ratings are divided into five groups: highest, above average, neutral, below
average and lowest. They represent a fund's historical risk/reward ratio
relative to other funds in its broad investment class as determined by
Morningstar, Inc. Morningstar ratings cover a variety of performance periods,
including 3-year, 5-year, 10-year and overall performance. The performance
factor for the overall rating is a weighted-average return performance (if
available) reflecting deduction of expenses and sales charges. Performance is
adjusted using quantitative techniques to reflect the risk profile of the fund.
The ratings are derived from a purely quantitative system that does not utilize
the subjective criteria customarily employed by rating agencies such as Standard
& Poor's and Moody's Investor Service, Inc.

CDA/WEISENBERGER'S MANAGEMENT RESULTS publishes mutual fund rankings and
-------------------------------------
is distributed monthly. The rankings are based entirely on total return
calculated by Weisenberger for periods such as year-to-date, 1-year, 3-year, 5-
year and 10-year. Mutual funds are ranked in general categories (e.g.,
international bond, international equity, municipal bond, and maximum capital
gain). Weisenberger rankings do not reflect deduction of sales charges or fees.

Performance information may also be used to compare the performance of the
Fund to certain widely acknowledged standards or indices for stock and bond
market performance, such as those listed below.

CONSUMER PRICE INDEX. The Consumer Price Index, published by the U.S.
--------------------
Bureau of Labor Statistics, is a statistical measure of changes, over time, in
the prices of goods and services in major expenditure groups.

DOW JONES INDUSTRIAL AVERAGE. The Dow Jones Industrial Average is a
----------------------------
market value-weighted and unmanaged index of 30 large industrial stocks traded
on the New York Stock Exchange.

LEHMAN BROTHERS GOVERNMENT/CORPORATE BOND INDEX. The Lehman Brothers
------------------------------------------------
Government/Corporate Bond Index is an index of publicly issued U.S. Treasury
obligations, debt obligations of U.S. government agencies (excluding mortgage-
backed securities), fixed-rate, non-convertible, investment-grade corporate debt
securities and U.S. dollar-denominated, SEC-registered non-convertible debt
issued by foreign governmental entities or international agencies used as a
general measure of the performance of fixed-income securities.

<PAGE>

LEHMAN BROTHERS 1-3 YEAR GOVERNMENT INDEX. The Index contains fixed rate
------------------------------------------
debt issues of the U.S. government or its agencies rated investment grade or
higher with at least one year maturity and an outstanding par value of at least
$100 million for U.S. government issues.

LEHMAN BROTHERS GOVERNMENT BOND INDEX. The Lehman Brothers Government
--------------------------------------
Bond Index is composed of all publicly issued, nonconvertible, domestic debt of
the U.S. government or any of its agencies, quasi-federal corporations, or
corporate debt guaranteed by the U.S. government.

LEHMAN BROTHERS MUNICIPAL BOND INDEX. The Lehman Brothers Municipal Bond
-------------------------------------
Index is computed from the prices of approximately 21,000 bonds consisting of
roughly 30% revenue bonds, 30% government obligation bonds, 27% insured bonds
and 13% prerefunded bonds.

MSCI-EAFE INDEX. The MSCI-EAFE Index contains over 1000 stocks from 20
----------------
different countries with Japan (approximately 50%), United Kingdom, France and
Germany being the most heavily weighted.

MSCI-EAFE EX-JAPAN INDEX. The MSCI-EAFE ex-Japan Index consists of all
-------------------------
stocks contained in the MSCI-EAFE Index, other than stocks from Japan.

MERRILL LYNCH GOVERNMENT/CORPORATE INDEX. The Merrill Lynch Government/
-----------------------------------------
Corporate Index is a composite of approximately 4,900 U.S. government and
corporate debt issues with at least $25 million outstanding, greater than one
year maturity, and credit ratings of investment grade or higher.

MERRILL LYNCH HIGH YIELD INDEX. The Merrill Lynch High Yield Index
-------------------------------
includes over 750 issues and represents public debt greater than $10 million
(original issuance rated BBB/BB and below).

RUSSELL 2000 INDEX. The Russell 2000 Index is comprised of the 2000
------------------
smallest of the 3000 largest U.S.-domiciled corporations, ranked by market
capitalization.

SALOMON BROTHERS WORLD GOVERNMENT BOND INDEX. The Salomon Brothers World
--------------------------------------------
Government Bond Index includes a broad range of institutionally-traded fixed-
rate government securities issued by the national governments of the nine
countries whose securities are most actively traded. The index generally
excludes floating- or variable-rate bonds, securities aimed principally at non-
institutional investors (such as U.S. Savings Bonds) and private-placement type
securities.

STANDARD & POOR'S/BARRA GROWTH INDEX. The Standard & Poor's/Barra Growth
-------------------------------------
Index is constructed by ranking the securities in the S&P 500 by price-to-book
ratio and including the securities with the highest price-to-book ratios that
represent approximately half of the market capitalization of the S&P 500.

26
<PAGE>

STANDARD & POOR'S/BARRA VALUE INDEX. The Standard & Poor's/Barra Value
------------------------------------
Index is constructed by ranking the securities in the S&P 500 by price-to-book
ratio and including the securities with the lowest price-to-book ratios that
represent approximately half of the market capitalization of the S&P 500.

STANDARD & POOR'S 500 COMPOSITE STOCK PRICE INDEX (THE "S&P 500"). The
------------------------------------------------------------------
S&P 500 is a market value-weighted and unmanaged index showing the changes in
the aggregate market value of 500 stocks relative to the base period 1941-43.
The S&P 500 is composed almost entirely of common stocks of companies listed on
the New York Stock Exchange, although the common stocks of a few companies
listed on the American Stock Exchange or traded over-the-counter are included.
The 500 companies represented include 400 industrial, 60 transportation and 40
financial services concerns. The S&P 500 represents about 80% of the market
value of all issues traded on the New York Stock Exchange. The S&P 500 is the
most common index for the overall U.S. stock market.

From time to time, articles about the Fund regarding performance, rankings
and other characteristics of the Fund may appear in publications including, but
not limited to, the publications included in Appendix A. In particular, some or
all of these publications may publish their own rankings or performance reviews
of mutual funds, including the Fund. References to or reprints of such articles
may be used in the Fund's promotional literature. References to articles
regarding personnel of the Loomis Sayles who have portfolio management
responsibility may also be used in the Fund's promotional literature. For
additional information about the Fund's advertising and promotional literature,
see Appendix B.

27
<PAGE>

PERFORMANCE DATA

The manner in which yield and total return of the Fund will be calculated
for public use is described above. The following table summarizes the
calculation of the Fund's yield at December 31, 1997 and the Fund's total return
(i) for the one-year period ended December 31, 1997 and (ii) for the period from
the Fund's commencement of operations to December 31, 1997.

Performance Data*

<TABLE>
<CAPTION>
Average
Average Annual
Annual Total
Total Return Return
for the from the Commencement
Current SEC Yield One-Year Period ended of Operations** through
at 12/31/97 12/31/97 12/31/97
----------- -------- --------
<S> <C> <C>
4.45% 7.25% 6.33%
</TABLE>

*Performance would have been lower if the management fee had not been waived and
certain other expenses had not been reimbursed by Loomis Sayles. In the absence
of the expense limitation, actual yield and total return would have been 3.76%
(yield), and 6.49% and 5.65% for the one-year period ended December 31, 1997 and
for the period from the Fund's commencement of operations to December 31, 1997,
respectively.

**Inception date of the Fund is June 1, 1995.

<PAGE>

APPENDIX A
PUBLICATIONS THAT MAY CONTAIN FUND INFORMATION

ABC and affiliates
Adam Smith's Money World
America On Line
Anchorage Daily News
Atlanta Constitution
Atlanta Journal
Arizona Republic
Austin American Statesman
Baltimore Sun
Bank Investment Marketing
Barron's
Bergen County Record (NJ)
Bloomberg Business News
Bond Buyer
Boston Business Journal
Boston Globe
Boston Herald
Broker World
Business Radio Network
Business Week
CBS and affiliates
CDA Investment Technologies
CFO
Changing Times
Chicago Sun Times
Chicago Tribune
Christian Science Monitor
Christian Science Monitor News Service
Cincinnati Enquirer
Cincinnati Post
CNBC
CNN
Columbus Dispatch
CompuServe
Dallas Morning News
Dallas Times-Herald
Denver Post
Des Moines Register
Detroit Free Press
Donoghues Money Fund Report
Dorfman, Dan (syndicated column)
Dow Jones News Service
Economist
FACS of the Week
Fee Adviser
Financial News Network
Financial Planning
Financial Planning on Wall Street
Financial Research Corp.
Financial Services Week
Financial World

Fitch Insights
Forbes
Fort Worth Star-Telegram
Fortune
Fox Network and affiliates
Fund Action
Fund Decoder
Global Finance
(the) Guarantor
Hartford Courant
Houston Chronicle
INC
Indianapolis Star
Individual Investor
Institutional Investor
International Herald Tribune
Internet
Investment Advisor
Investment Company Institute
Investment Dealers Digest
Investment Profiles
Investment Vision
Investor's Daily
IRA Reporter
Journal of Commerce
Kansas City Star
KCMO (Kansas City)
KOA-AM (Denver)
LA Times
Leckey, Andrew (syndicated column)
Life Association News
Lifetime Channel
Miami Herald
Milwaukee Sentinel
Money Magazine
Money Maker
Money Management Letter
Morningstar
Mutual Fund Market News
Mutual Funds Magazine
National Public Radio
National Underwriter
NBC and affiliates
New England Business
New England Cable News
New Orleans Times-Picayune
New York Daily News
New York Times
Newark Star Ledger
Newsday
Newsweek

29
<PAGE>

Nightly Business Report
Orange County Register
Orlando Sentinel
Palm Beach Post
Pension World
Pensions and Investments
Personal Investor
Philadelphia Inquirer
Porter, Sylvia (syndicated column)
Portland Oregonian
Prodigy
Public Broadcasting Service
Quinn, Jane Bryant (syndicated column)
Registered Representative
Research Magazine
Resource
Reuters
Rocky Mountain News
Rukeyser's Business (syndicated column)
Sacramento Bee
San Diego Tribune
San Francisco Chronicle
San Francisco Examiner
San Jose Mercury
Seattle Post-Intelligencer
Seattle Times
Securities Industry Management
Smart Money
St. Louis Post Dispatch
St. Petersburg Times
Standard & Poor's Outlook
Standard & Poor's Stock Guide
Stanger's Investment Advisor
Stockbroker's Register
Strategic Insight
Tampa Tribune
Time
Tobias, Andrew (syndicated column)
Toledo Blade
UP
US News and World Report
USA Today
USA TV Network
Value Line
Wall Street Journal
Wall Street Letter
Wall Street Week
Washington Post
WBZ
WBZ-TV
WCVB-TV
WEEI
WHDH
Worcester Telegram

World Wide Web
Worth Magazine
WRKO

30
<PAGE>

APPENDIX B
ADVERTISING AND PROMOTIONAL LITERATURE

Loomis Sayles Investment Trust advertising and promotional material may include,
but is not limited to, discussions of the following information:

Loomis Sayles Investment Trust's participation in wrap fee and no
transaction fee programs

Characteristics of Loomis Sayles including the number and locations of its
offices, its investment practices and clients

Specific and general investment philosophies, strategies, processes and
techniques

Specific and general sources of information, economic models, forecasts
and data services utilized, consulted or considered in the course of
providing advisory or other services

Industry conferences at which Loomis Sayles participates

Current capitalization, levels of profitability and other financial
information

Identification of portfolio managers, researchers, economists, principals
and other staff members and employees

The specific credentials of the above individuals, including but not
limited to, previous employment, current and past positions, titles and
duties performed, industry experience, educational background and degrees,
awards and honors

Specific identification of, and general reference to, current individual,
corporate and institutional clients, including pension and profit sharing
plans

Current and historical statistics relating to:

-total dollar amount of assets managed
-Loomis Sayles assets managed in total and by Fund
-the growth of assets
-asset types managed

References may be included in Loomis Sayles Investment Trust's advertising
and promotional literature about 401(k) and retirement plans, if any, that offer
the Fund. The information may include, but is not limited to:

Specific and general references to industry statistics regarding 401(k)
and retirement plans including historical information and industry trends
and forecasts regarding the growth of assets, numbers or plans, funding
vehicles, participants, sponsors and other demographic data relating to
plans, participants and sponsors, third party and other administrators,
benefits consultants and firms with whom Loomis Sayles may or may not have
a relationship.

Specific and general reference to comparative ratings, rankings and other
forms of evaluation as well as statistics regarding the Fund as a 401(k) or
retirement plan funding vehicle produced by industry authorities, research
organizations and publications.

31
<PAGE>

LOOMIS SAYLES INVESTMENT TRUST

LOOMIS SAYLES CORE FIXED INCOME FUND

STATEMENT OF ADDITIONAL INFORMATION

April 22, 1998

This Statement of Additional Information is not a prospectus. This Statement of
Additional Information relates to the Prospectus (the "Prospectus") of Loomis
Sayles Core Fixed Income Fund, a series of Loomis Sayles Investment Trust, dated
April 22, 1998, and should be read in conjunction therewith. A copy of the
Prospectus may be obtained from Loomis Sayles Investment Trust, One Financial
Center, Boston, Massachusetts 02111.
<PAGE>

TABLE OF CONTENTS

INVESTMENT OBJECTIVE, POLICIES AND RESTRICTIONS................ -3-

MANAGEMENT OF THE TRUST........................................ -9-

INVESTMENT ADVISORY AND OTHER SERVICES......................... -12-

PORTFOLIO TRANSACTIONS AND BROKERAGE........................... -14-

DESCRIPTION OF THE TRUST....................................... -16-

HOW TO BUY SHARES.............................................. -18-

NET ASSET VALUE................................................ -18-

REDEMPTIONS.................................................... -19-

INCOME DIVIDENDS, CAPITAL GAIN DISTRIBUTIONS AND TAX STATUS.... -20-

FINANCIAL STATEMENTS........................................... -22-

CALCULATION OF YIELD AND TOTAL RETURN.......................... -22-

PERFORMANCE COMPARISONS........................................ -23-

PERFORMANCE DATA............................................... -26-

APPENDIX A
PUBLICATIONS THAT MAY CONTAIN FUND INFORMATION............ -28-

APPENDIX B
ADVERTISING AND PROMOTIONAL LITERATURE.................... -30-

2
<PAGE>

INVESTMENT OBJECTIVE, POLICIES AND RESTRICTIONS

The investment objective and policies of the Loomis Sayles Core Fixed
Income Fund (the "Fund"), a series of Loomis Sayles Investment Trust (the
"Trust"), are summarized in the Prospectus under "Investment Objective and
Policies" and "More Information About the Fund's Investments." The investment
policies of the Fund set forth in the Prospectus and in this Statement of
Additional Information may be changed by Loomis, Sayles & Company, L.P. ("Loomis
Sayles"), the Fund's investment adviser, subject to review and approval by the
Trust's board of trustees (the "Trustees"), without shareholder approval except
that the investment objective of the Fund as set forth in the Prospectus and any
Fund policy explicitly identified as "fundamental" may not be changed without
the approval of the holders of a majority of the outstanding shares of the Fund
(which means the lesser of (i) 67% of the shares of the Fund represented at a
meeting at which at least 50% of the outstanding shares are represented or (ii)
more than 50% of the outstanding shares).

The Fund will not:

*(1) Act as underwriter, except to the extent that, in connection with
the disposition of portfolio securities, it may be deemed to be an
underwriter under certain federal securities laws.

*(2) Invest in oil, gas or other mineral leases, rights or royalty
contracts or in real estate, commodities or commodity contracts.
(This restriction does not prevent the Fund from investing in
issuers that invest or deal in the foregoing types of assets or from
purchasing securities that are secured by real estate.)

*(3) Make loans. (For purposes of this investment restriction, neither
(i) entering into repurchase agreements nor (ii) purchasing bonds,
debentures, commercial paper, corporate notes and similar evidences
of indebtedness, which are a part of an issue to the public, is
considered the making of a loan.)

*(4) Change its classification pursuant to Section 5(b) of the Investment
Company Act of 1940, as amended (the "1940 Act"), from a
"diversified" to a "non-diversified" management investment company.

*(5) Purchase any security (other than U.S. Government Securities) if, as
a result, more than 25% of the Fund's total assets (taken at current
value) would be invested in any one industry (in the utilities
category, gas, electric, water and telephone companies will be
considered as being in separate industries.)

3
<PAGE>

*(6) Borrow money in excess of 10% of its total assets (taken at cost) or
5% of its total assets (taken at current value), whichever is lower,
nor borrow any money except as a temporary measure for extraordinary
or emergency purposes; however, the Fund's use of reverse repurchase
agreements and "dollar roll" arrangements shall not constitute
borrowing by the Fund for purposes of this restriction.

*(8) Issue senior securities other than any borrowing permitted by
restriction (6) above. (For the purposes of this restriction none of
the following is deemed to be a senior security: any pledge,
mortgage, hypothecation or other encumbrance of assets; any
collateral arrangements with respect to options, futures contracts
and options on futures contracts and with respect to initial and
variation margin; and the purchase or sale of or entry into options,
forward contracts, futures contracts, options on futures contracts,
swap contracts or any other derivative investments to the extent
that Loomis Sayles determines that the Fund is not required to treat
such investments as senior securities pursuant to the pronouncements
of the Securities and Exchange Commission (the "SEC") or its staff.)

Although the Fund has no current intention of investing in repurchase
agreements, the Fund intends, based on the views of the staff of the SEC, to
restrict its investments, if any, in repurchase agreements maturing in more than
seven days, together with other investments in illiquid securities, to the
percentage permitted by restriction (7) above.

Although authorized to invest in restricted securities, the Fund, as a
matter of non-fundamental operating policy, currently does not intend to invest
in such securities, except Rule 144A securities.

Portfolio Turnover
- ------------------

4
<PAGE>

U.S. Government Securities
- --------------------------

. "Fannie Maes" - The Federal National Mortgage Association ("FNMA") is
-------------
a government-sponsored corporation owned entirely by private stockholders that
purchases residential mortgages from a list of approved seller/servicers.
Fannie Maes are pass-through securities issued by FNMA that are guaranteed as to
timely payment of principal and interest by FNMA but are not backed by the full
faith and credit of the U.S. Government.

5
<PAGE>

FHLMC guarantees the timely payment of interest and ultimate collection of
principal, but Freddie Macs are not backed by the full faith and credit of the
U.S. Government.

When-Issued Securities
- ----------------------

As described in the Prospectus, the Fund may enter into agreements with
banks or broker-dealers for the purchase or sale of securities at an agreed-upon
price on a specified future date. Such agreements might be entered into, for
example, when the Fund anticipates a decline in interest rates and is able to
obtain a more advantageous yield by committing currently to purchase securities
to be issued later. When the Fund purchases securities in this manner (i.e. on
a when-issued or delayed-delivery basis), it is required to create a segregated
account with the Trust's custodian and to maintain in that account liquid assets
in an amount equal to or greater than, on a daily basis, the amount of the
Fund's when-issued or delayed-delivery commitments. The Fund will make
commitments to purchase on a when-issued or delayed-delivery basis only
securities meeting the Fund's investment criteria. The Fund may take delivery
of these securities or, if it is deemed advisable as a matter of investment
strategy, the Fund may sell these securities before the settlement date. When
the time comes to pay for when-issued or delayed-delivery securities, the Fund
will meet its obligations from then available cash flow or the sale of
securities, or from the sale of the when-issued or delayed-delivery securities
themselves (which may have a value greater or less than the Fund's payment
obligation).

Convertible Securities
- ----------------------

Convertible securities include corporate bonds, notes or preferred stocks
of U.S. or foreign issuers that can be converted into (that is, exchanged for)
common stocks or other equity securities at a stated price or rate. Convertible
securities also include other securities, such as warrants, that provide an
opportunity for equity participation. Because convertible securities can be
converted into equity securities, their value will normally vary in some
proportion with those of the underlying equity securities. Convertible
securities usually provide a higher yield than the underlying equity security,
however, so that when the price of the underlying equity security falls, the
decline in the price of the convertible security may sometimes be less
substantial than that of the underlying equity security. Due to the conversion
feature, convertible securities generally yield less than nonconvertible fixed
income securities of similar credit quality and maturity. The Fund's investment
in convertible securities may at times include securities that have a mandatory
conversion feature, pursuant to which the securities convert automatically into
common stock at a specified date and

6
<PAGE>

conversion ratio, or that are convertible at the option of the issuer. Because
conversion is not at the option of the holder, the Fund may be required to
convert the security into the underlying common stock even at times when the
value of the underlying common stock has declined substantially.

Zero Coupon Bonds
- -----------------

Repurchase Agreements
- ---------------------

The Fund may enter into repurchase agreements, by which the Fund purchases
a security and obtains a simultaneous commitment from the seller (a bank or, to
the extent permitted by the 1940 Act, a recognized securities dealer) to
repurchase the security at an agreed upon price and date (usually seven days or
less from the date of original purchase). The resale price is in excess of the
purchase price and reflects an agreed upon market rate unrelated to the coupon
rate on the purchased security. Such transactions afford the Fund the
opportunity to earn a return on temporarily available cash. Although the
underlying security may be a bill, certificate of indebtedness, note or bond
issued by an agency, authority or instrumentality of the U.S. Government, the
obligation of the seller is not guaranteed by the U.S. Government and there is a
risk that the seller may fail to repurchase the underlying security. In such
event, the Fund would attempt to exercise rights with respect to the underlying
security, including possible disposition in the market. However, the Fund may
be subject to various delays and risks of loss, including (a) possible declines
in the value of the underlying security during the period while the Fund seeks
to enforce its rights thereto and (b) inability to enforce rights and the
expenses involved in attempted enforcement.

7
<PAGE>

Lower Rated Fixed Income Securities
- -----------------------------------

The Fund will purchase securities rated at least BBB- by Standard & Poor's
("S&P") and Baa3 by Moody's Investors Service, Inc. ("Moody's"), or if unrated,
determined to be of comparable quality by Loomis Sayles. In the event that the
credit rating of a security held by the Fund falls below investment grade (or,
in the case of unrated securities, Loomis Sayles determines that the quality of
such security has deteriorated below investment grade), the Fund will not be
obligated to dispose of such security and may continue to hold such security if,
in the opinion of Loomis Sayles, such investment is appropriate in the
circumstances. Securities rated below investment grade ("lower rated fixed
income securities") generally provide higher yields, but are subject to greater
credit and market risk than higher quality fixed income securities. Lower rated
fixed income securities are considered speculative with respect to the ability
of the issuer to meet principal and interest payments. Achievement of the
Fund's investment objective through investment in lower rated fixed income
securities may be more dependent on Loomis Sayles's credit analysis than is the
case with higher quality bonds. The market for lower rated fixed income
securities may be more severely affected than other financial markets by
economic recession or substantial interest rate increases. The value and
liquidity of lower rated fixed income securities may be diminished by adverse
publicity and investor perceptions. In addition, legislation that limits the
tax benefits to issuers or holders of lower rated fixed income securities or
that limits the ability of certain categories of financial institutions to
invest in these securities may adversely affect their market value. The
secondary market for lower rated fixed income securities may be less liquid than
the secondary market for higher rated fixed income securities. This lack of
liquidity at certain times may affect the values of these securities and may
make the valuation and sale of these securities by the Fund more difficult.
Certain lower-rated fixed income securities do not pay interest on a current
basis. However, the Fund will accrue and distribute this interest on a current
basis, and may be required to sell securities at times when Loomis Sayles would
not otherwise deem it advisable to do so to generate cash for distributions.
Securities of below investment grade quality are commonly referred to as "junk
bonds." Securities in the lowest rating categories may be in poor standing or
in default. Investment grade fixed income securities rated BBB by S&P or Baa by
Moody's may share some of the characteristics described above.