<PAGE>
SEI DAILY INCOME TRUST
MONEY MARKET FUND
PRIME OBLIGATION FUND
GOVERNMENT FUND
GOVERNMENT II FUND
TREASURY FUND
TREASURY II FUND
FEDERAL SECURITIES FUND
SUPPLEMENT DATED OCTOBER 1, 1998, TO THE
CLASS A AND CLASS B PROSPECTUS DATED MAY 31, 1998.
THIS SUPPLEMENT PROVIDES NEW AND ADDITIONAL INFORMATION BEYOND THAT CONTAINED IN
THE PROSPECTUS. IT SHOULD BE RETAINED AND READ IN CONJUNCTION WITH SUCH
PROSPECTUS.
As of September 10, 1998, the "Portfolios" of SEI Daily Income Trust will be
redesignated as "Funds."
------------------------
The Annual Operating Expense tables found on page 2 and 3 will be replaced with
the following:
ANNUAL OPERATING EXPENSES (as a percentage of average net assets) Class A
<TABLE>
<CAPTION>
<S> <C> <C> <C> <C>
MONEY PRIME
MARKET OBLIGATION GOVERNMENT GOVERNMENT II
FUND FUND FUND FUND
Management/ Advisory fees (after
fee waiver) (1) .11% .16% .15% .15%
12b-1 Fees None None None None
Total Other Expenses .07% .04% .05% .05%
Shareholder Servicing Fees (2) .00% .00% .00% .00%
Total Operating Expenses
(after fee waivers)(3)(4) .18% .20% .20% .20%
<CAPTION>
FEDERAL
TREASURY TREASURY II SECURITIES
FUND FUND FUND
Management/ Advisory fees (after
fee waiver) (1) .10% .21% .58%
12b-1 Fees None None None
Total Other Expenses .10% .04% .02%
Shareholder Servicing Fees (2) .00% .00% .00%
Total Operating Expenses
(after fee waivers)(3)(4) .20% .25% .60%
</TABLE>
(1) The Manger and Adviser have waived a portion of their fees, and the
management/advisory fees shown reflect these waivers. Absent such waivers,
management' advisory fees would be .35% for the Money Market Fund, 26% for
the Government, Treasury and Treasury II Funds, 62% for the Federal
Securities Fund and .21% for the Prime Obligation and Government II Funds.
Management/advisory fee for the Money Market Fund has been restated to
reflect current expenses.
(2) Reflects the anticipated level of Shareholder Servicing Fees for Class A
shares. Please see "Distribution and Shareholder Servicing,"
(3) Absent these fee waivers, total operating expenses for the Class A shares of
the Funds would be .64% for the Money Market Fund, .51% for the Treasury II
Fund and .89% for the Federal Securities Fund. Total operating expenses for
the Money Market and Treasury Funds have been restated to reflect current
expenses.
(4) Total operating expenses for the Federal Securities Fund are estimated for
the current fiscal year.
<PAGE>
EXAMPLE Class A
<TABLE>
<CAPTION>
1 YR. 3 YRS. 5 YRS. 10 YRS.
<S> <C> <C> <C> <C>
An investor would pay the following expenses on a
$1,000 investment assuming (1) a 5% annual return
and (2) redemption at the end of each time period:
Money Market Fund $2 $ 6 $11 $26
Prime Obligation Fund 2 6 11 26
Government Fund 2 6 11 26
Government II Fund 2 6 11 26
Treasury Fund 2 6 11 26
Treasury II Fund 3 8 14 32
Federal Securities Fund 6 19 33 75
</TABLE>
THE EXAMPLE SHOULD NOT BE CONSIDERED A REPRESENTATION OF PAST OR FUTURE
EXPENSES. ACTUAL EXPENSES MAY BE GREATER OR LESS THAN THOSE SHOWN. THE PURPOSE
OF THIS TABLE IS TO ASSIST THE INVESTOR IN UNDERSTANDING THE VARIOUS COSTS AND
EXPENSES THAT MAY BE DIRECTLY OR INDIRECTLY BORNE BY INVESTORS IN CLASS A SHARES
OF THE FUNDS. A PERSON WHO PURCHASES SHARES THROUGH A FINANCIAL INSTITUTION MAY
BE CHARGED SEPARATE FEES BY THAT INSTITUTION. EACH OF THE FUNDS, EXCEPT THE
FEDERAL SECURITIES FUND, ALSO OFFERS CLASS B, CLASS C AND SWEEP CLASS SHARES,
AND THE GOVERNMENT FUND ALSO OFFERS CNI CLASS SHARES, WHICH ARE SUBJECT TO THE
SAME EXPENSES, EXCEPT THAT CLASS B, CLASS C, CNI CLASS, AND SWEEP CLASS SHARES
EACH HAVE DIFFERENT DISTRIBUTION AND/OR SHAREHOLDER SERVICING COSTS. ADDITIONAL
INFORMATION MAY BE FOUND UNDER "THE MANAGER," "THE ADVISER" AND "DISTRIBUTION
AND SHAREHOLDER SERVICING."
<PAGE>
ANNUAL OPERATING EXPENSES (as a percentage of average net assets) Class B
<TABLE>
<CAPTION>
MONEY PRIME
MARKET OBLIGATION GOVERNMENT GOVERNMENT II
FUND FUND FUND FUND
<S> <C> <C> <C> <C>
Management/Advisory fees
(after fee waiver) (1) .11% .16% .15% .15%
12b-1 Fees None None None None
Total Other Expenses .37% .34% .35% .35%
Shareholder Servicing Fees .25% .25% .25% .25%
Total Operating Expenses
(after fee waivers (2) .48% .50% .50% .50%
<CAPTION>
TREASURY TREASURY II
FUND FUND
<S> <C> <C>
Management/Advisory fees
(after fee waiver) (1) .10% .21%
12b-1 Fees None None
Total Other Expenses .40% .34%
Shareholder Servicing Fees .25% .25%
Total Operating Expenses
(after fee waivers (2) .50% .55%
</TABLE>
(1) The Manger and Adviser have waived a portion of their fees, and the
management/advisory fees shown reflect these waivers. Absent such waivers,
management/advisory fees would be .35% for the Money Market Fund, 26% for
the Government, Treasury and Treasury II Funds and .21% for the Prime
Obligation and Government II Funds. Management/advisory fee for the Money
Market Fund has been restated to reflect current expenses.
(2) Absent this fee waiver, total operating expenses for the Class B shares of
the Funds would be .70% for the Money Market Fund, .55% for the Prime
Obligation Fund, .61% for the Government Fund, .56% for the Government II
Fund, .65% for the Treasury Fund and .60% for the Treasury II Fund. Total
operating expenses for the Money Market and Treasury Funds have been
restated to reflect current expenses.
EXAMPLE Class B
<TABLE>
<CAPTION>
1 YR. 3 YRS. 5 YRS. 10 YRS.
<S> <C> <C> <C> <C>
An investor would pay the following expenses on a
$1,000 investment assuming (1) a 5% annual return
and (2) redemption at the end of each time period:
Money Market Fund $5 $16 $28 $63
Prime Obligation Fund $5 $16 $28 $63
Government Fund $5 $16 $28 $63
Government II Fund $5 $16 $28 $63
Treasury Fund $5 $16 $28 $63
Treasury II Fund $6 $18 $31 $69
</TABLE>
THE EXAMPLE SHOULD NOT BE CONSIDERED A REPRESENTATION OF PAST OR FUTURE
EXPENSES. ACTUAL EXPENSES MAY BE GREATER OR LESS THAN THOSE SHOWN. THE PURPOSE
OF THIS TABLE IS TO ASSIST THE INVESTOR IN UNDERSTANDING THE VARIOUS COSTS AND
EXPENSES THAT MAY BE DIRECTLY OR INDIRECTLY BORNE BY INVESTORS IN CLASS B SHARES
OF THE FUNDS. A PERSON WHO PURCHASES SHARES THROUGH A FINANCIAL INSTITUTION MAY
BE CHARGED SEPARATE FEES BY THAT INSTITUTION. EACH OF THE FUNDS ALSO OFFERS
CLASS A, CLASS C AND SWEEP CLASS SHARES, AND THE GOVERNMENT FUND ALSO OFFERS CNI
CLASS SHARES, WHICH ARE SUBJECT TO THE SAME EXPENSES, EXCEPT THAT CLASS A, CLASS
C, CNI CLASS, AND SWEEP CLASS SHARES EACH HAVE DIFFERENT DISTRIBUTION AND/OR
SHAREHOLDER SERVICING COSTS. ADDITIONAL INFORMATION MAY BE FOUND UNDER "THE
MANAGER," "THE ADVISER" AND "DISTRIBUTION AND SHAREHOLDER SERVICING."
------------------------------
The following disclosure is inserted on page 8 of the Prospectus under the
description of the Government II Fund:
Since the Government II Fund invests exclusively in U.S. Treasury
Obligations, its income is not subject to state or local taxation.
--------------------------
The prospectus is hereby amended to reflect these changes.
PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE.
<PAGE>
SEI DAILY INCOME TRUST
MONEY MARKET FUND
PRIME OBLIGATION FUND
GOVERNMENT FUND
GOVERNMENT II FUND
TREASURY FUND
TREASURY II FUND
SUPPLEMENT DATED OCTOBER 1, 1998, TO THE
SWEEP CLASS PROSPECTUS DATED MAY 31, 1998.
THIS SUPPLEMENT PROVIDES NEW AND ADDITIONAL INFORMATION BEYOND THAT CONTAINED IN
THE PROSPECTUS. IT SHOULD BE RETAINED AND READ IN CONJUNCTION WITH SUCH
PROSPECTUS.
As of September 10, 1998, the "Portfolios" of SEI Daily Income Trust will be
redesignated as "Funds."
------------------------
The Annual Operating Expense table found on page 2 will be replaced with the
following:
ANNUAL OPERATING EXPENSES (as a percentage of average net assets) Sweep Class
<TABLE>
<CAPTION>
MONEY PRIME
MARKET OBLIGATION GOVERNMENT GOVERNMENT II TREASURY TREASURY II
FUND FUND FUND FUND FUND FUND
<S> <C> <C> <C> <C> <C> <C>
Management/Advisory Fees
(after fee waiver)(1) .11% .16% .15% .15% .10% .21%
12b-1 Fees .50% .50% .50% .50% .50% .50%
Total Other Expenses .32% .29% .30% .30% .35% .29%
Shareholder Servicing Fees .25% .25% .25% .25% .25% .25%
Total Operating Expenses
(after fee waivers)(2) .93% .95% .95% .95% .95% 1.00%
</TABLE>
(1) The Manager and Adviser have waived a portion of their fees, and the
management/advisory fees shown reflect these waivers. Absent such waivers,
management/advisory fees would be .35% for the Money Market Fund, 26% for
the Government, Treasury and Treasury II Funds and .21% for the Prime
Obligation and Government II Funds.
(2) Absent this fee waiver, total operating expenses for the Sweep Class shares
of the Funds would be 1.14% for the Money Market Fund, 1.01% for the Prime
Obligation Fund, 1.06% for the Government Fund, 1.01% for the Government II
Fund, 1.10% for the Treasury Fund and 1.06% for the Treasury II Fund. Total
operating expenses for the Money Market and Treasury Funds have been
restated to reflect current expenses.
<PAGE>
EXAMPLE
Sweep Class
<TABLE>
<CAPTION>
1 YR. 3 YRS. 5 YRS. 10 YRS.
<S> <C> <C> <C> <C>
An investor would pay the following expenses on a
$1,000 investment assuming (1) a 5% annual return
and (2) redemption at the end of each time period:
Money Market Fund $ 10 $ 30 $ 53 $ 117
Prime Obligation Fund 10 30 53 117
Government Fund 10 30 53 117
Government II Fund 10 30 53 117
Treasury Fund 10 30 53 117
Treasury II Fund 10 32 55 122
</TABLE>
THE EXAMPLE SHOULD NOT BE CONSIDERED A REPRESENTATION OF PAST OR FUTURE
EXPENSES. ACTUAL EXPENSES MAY BE GREATER OR LESS THAN THOSE SHOWN. THE PURPOSE
OF THIS TABLE IS TO ASSIST THE INVESTOR IN UNDERSTANDING THE VARIOUS COSTS AND
EXPENSES THAT MAY BE DIRECTLY OR INDIRECTLY BORNE BY INVESTORS IN SWEEP CLASS
SHARES OF THE FUNDS. A PERSON WHO PURCHASES SHARES THROUGH A FINANCIAL
INSTITUTION MAY BE CHARGED SEPARATE FEES BY THAT INSTITUTION. EACH OF THE FUNDS
ALSO OFFERS CLASS A, CLASS B AND CLASS C SHARES, AND THE GOVERNMENT FUND ALSO
OFFERS CNI CLASS SHARES, WHICH ARE SUBJECT TO THE SAME EXPENSES, EXCEPT THAT
CLASS A, CLASS B, CLASS C AND CNI CLASS SHARES EACH HAVE DIFFERENT DISTRIBUTION
AND/OR SHAREHOLDER SERVICING COSTS. ADDITIONAL INFORMATION MAY BE FOUND UNDER
"THE MANAGER," "THE ADVISER" AND "DISTRIBUTION AND SHAREHOLDER SERVICING."
------------------------------
The following disclosure is inserted on page 5 of the Prospectus under the
description of the Government II Fund:
Since the Government II Fund invests exclusively in U.S. Treasury
Obligations, its income is not subject to state or local taxation.
------------------------
The prospectus is hereby amended to reflect these changes.
PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE.
<PAGE>
SEI DAILY INCOME TRUST
MONEY MARKET FUND
PRIME OBLIGATION FUND
GOVERNMENT FUND
GOVERNMENT II FUND
TREASURY FUND
TREASURY II FUND
SUPPLEMENT DATED OCTOBER 1, 1998, TO THE
CLASS C PROSPECTUS DATED MAY 31, 1998.
THIS SUPPLEMENT PROVIDES NEW AND ADDITIONAL INFORMATION BEYOND THAT CONTAINED IN
THE PROSPECTUS. IT SHOULD BE RETAINED AND READ IN CONJUNCTION WITH SUCH
PROSPECTUS.
As of September 10, 1998, the "Portfolios" of SEI Daily Income Trust will be
redesignated as "Funds."
------------------------
The Annual Operating Expense table found on page 2 will be replaced with the
following:
ANNUAL OPERATING EXPENSES (as a percentage of average net assets) Class C
<TABLE>
<CAPTION>
MONEY PRIME
MARKET OBLIGATION GOVERNMENT GOVERNMENT II TREASURY TREASURY II
FUND FUND FUND FUND FUND FUND
<S> <C> <C> <C> <C> <C> <C>
Management/Advisory fees
(after fee waiver)(1) .11% .16% .15% .15% .10% .21%
12b-1 Fees None None None None None None
Total Other Expenses .57% .54% .55% .55% .60% .54%
Shareholder Servicing Fees .25% .25% .25% .25% .25% .25%
Total Operating Expenses
(after fee waivers(2) .68% .70% .70% .70% .70% .75%
</TABLE>
(1) The Manager and Adviser have waived a portion of their fees, and the
management/advisory fees shown reflect these waivers. Absent such waivers,
management/advisory fees would be .35% for the Money Market Fund, 26% for
the Government, Treasury and Treasury II Funds and .21% for the Prime
Obligation and Government II Funds. Management/advisory fee for the Money
Market Fund has been restated to reflect current expenses.
(2) Absent this fee waiver, total operating expenses for the Class C shares of
the Funds would be .90% for the Money Market Fund, .76% for the Prime
Obligation Fund, .81% for the Government Fund, .76% for the Government II
Fund, .85% for the Treasury Fund and .81% for the Treasury II Fund. Total
operating expenses for the Money Market and Treasury Funds have been
restated to reflect current expenses.
<PAGE>
EXAMPLE Class C
<TABLE>
<CAPTION>
1 10
YR. 3 YRS. 5 YRS. YRS.
<S> <C> <C> <C> <C>
An investor would pay the following expenses on a
$1,000 investment assuming (1) a 5% annual return
and (2) redemption at the end of each time period:
Money Market Fund $7 $ 22 $ 39 $87
Prime Obligation Fund 7 22 39 87
Government Fund 7 22 39 87
Government II Fund 7 22 39 87
Treasury Fund 7 22 39 87
Treasury II Fund 8 24 42 93
</TABLE>
THE EXAMPLE SHOULD NOT BE CONSIDERED A REPRESENTATION OF PAST OR FUTURE
EXPENSES. ACTUAL EXPENSES MAY BE GREATER OR LESS THAN THOSE SHOWN. THE PURPOSE
OF THIS TABLE IS TO ASSIST THE INVESTOR IN UNDERSTANDING THE VARIOUS COSTS AND
EXPENSES THAT MAY BE DIRECTLY OR INDIRECTLY BORNE BY INVESTORS IN CLASS C SHARES
OF THE FUNDS. A PERSON WHO PURCHASES SHARES THROUGH A FINANCIAL INSTITUTION MAY
BE CHARGED SEPARATE FEES BY THAT INSTITUTION. EACH OF THE FUNDS ALSO OFFERS
CLASS A, CLASS B AND SWEEP CLASS SHARES, AND THE GOVERNMENT FUND ALSO OFFERS CNI
CLASS SHARES, WHICH ARE SUBJECT TO THE SAME EXPENSES, EXCEPT THAT CLASS A, CLASS
B, CNI CLASS, AND SWEEP CLASS SHARES EACH HAVE DIFFERENT DISTRIBUTION AND/OR
SHAREHOLDER SERVICING COSTS. ADDITIONAL INFORMATION MAY BE FOUND UNDER "THE
MANAGER," "THE ADVISER" AND "DISTRIBUTION AND SHAREHOLDER SERVICING."
------------------------------
The following disclosure is inserted on page 5 of the Prospectus under the
description of the Government II Fund:
Since the Government II Fund invests exclusively in U.S. Treasury
Obligations, its income is not subject to state or local taxation.
------------------------
The prospectus is hereby amended to reflect these changes.
PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE.
