Form 4
1. Name and Address of Reporting Person -
Peter R. Kellogg
C/O Spear, Leeds & Kellogg
120 Broadway
New York, NY 10271
2. Issuer Name and Ticker or Trading Symbol -- Thoratec
Labs Corp. ("THOR")
3. IRS or Social Security Number of Reporting Person
(Voluntary)
4. Statement for Month/Year -- August, 1999
5. If Amendment, Date of Original (Month/Year)
6. Relationship of Reporting Person to Issuer -- 10% Owner
Table I - Non-Derivative Securities Acquired, Disposed of,
or Beneficially Owned
1. Title of Security -- Common Stock $.01 Par Value
2. Transaction Date. - August 17, 1999.
3. Transaction Code - P.
4. Securities Acquired (A) or Disposed of (D)
Amount = 77,000 (A) or (D) = A.
Price 8.6875.
5. Amount of Securities Beneficially Owned at End of Month
= 162,100.
6. Ownership Form -- (D).
7. Nature of Indirect Beneficial Ownership -- N/A.
5. Amount of Securities Beneficially Owned at End of
Month = 1,756,350.
6. Ownership Form - (I).
7. Nature of Indirect Beneficial Ownership - I.A.T.
Reinsurance Syndicate Ltd., a Bermuda Corporation of
which Mr. Kellogg is the sole holder of voting stock.
Mr. Kellogg disclaims beneficial ownership of these
shares.
5. Amount of Securities Beneficially Owned at End of Month
= 400,000
6. Ownership Form = (I).
7. Nature of Indirect Beneficial Ownership - Peter R. and
Cynthia K. Kellogg Foundation. Mr. Kellogg disclaims
beneficial ownership of these shares.
Table II - Derivative Securities Acquired, Disposed of, or
Beneficially Owned
(e.g., puts, calls, warrants, options, convertible
securities)
1. Title of Derivative Security. N/A.
2. Conversion or Exercise Price of Derivative Security. N/A.
3. Transaction Date. N/A.
4. Transaction Code. N/A.
5. Number of Derivative Securities Acquired or Disposed N/A.
6. Date Exercisable and Expiration Date N/A.
7. Title and Amount of Underlying Securities N/A.
8. Price of Derivative Securities N/A.
9. Number of Derivative Securities Beneficially Owned at End
of Month N/A.
10.Ownership Form of Derivative Security
N/A.
11.Nature of Indirect Beneficial Ownership N/A.
