Sec Form 4 Filing - BVF PARTNERS L P/IL @ Rain Therapeutics Inc. - 2021-04-23

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person BVF PARTNERS L P/IL 2. Issuer Name and Ticker or Trading Symbol Rain Therapeutics Inc. [ RAIN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) X __ Other (specify below) See Remarks (Last) (First) (Middle) 44 MONTGOMERY STREET, 40TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 04/23/2021 (Street) SAN FRANCISCO, CA94104 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock, $0.001 par value ( 1 ) 04/23/2021 C 115,293 A 115,293 D ( 2 ) Common Stock, $0.001 par value ( 1 ) 04/23/2021 A 546,346 A $ 17 661,639 D ( 2 ) Common Stock, $0.001 par value ( 1 ) 04/23/2021 A 53,303 A $ 15.9285 714,942 D ( 2 ) Common Stock, $0.001 par value ( 1 ) 04/26/2021 A 14,790 A $ 14.9009 729,732 D ( 2 ) Non-Voting Common Stock, $0.001 par value ( 1 ) 04/23/2021 C 832,261 A 832,261 D ( 2 ) Non-Voting Common Stock, $0.001 par value ( 1 ) 04/23/2021 C 1,068,554 A 1,900,815 D ( 2 ) Common Stock, $0.001 par value ( 1 ) 04/23/2021 C 84,350 A 84,350 D ( 3 ) Common Stock, $0.001 par value ( 1 ) 04/23/2021 A 398,300 A $ 17 482,650 D ( 3 ) Common Stock, $0.001 par value ( 1 ) 04/23/2021 A 38,858 A $ 15.9285 521,508 D ( 3 ) Common Stock, $0.001 par value ( 1 ) 04/26/2021 A 10,876 A $ 14.9009 532,384 D ( 3 ) Non-Voting Common Stock, $0.001 par value ( 1 ) 04/23/2021 C 553,359 A 553,359 D ( 3 ) Non-Voting Common Stock, $0.001 par value ( 1 ) 04/23/2021 C 837,397 A 1,390,756 D ( 3 ) Common Stock, $0.001 par value ( 1 ) 04/23/2021 C 17,390 A 17,390 D ( 4 ) Common Stock, $0.001 par value ( 1 ) 04/23/2021 A 62,948 A $ 17 80,338 D ( 4 ) Common Stock, $0.001 par value ( 1 ) 04/23/2021 A 6,141 A $ 15.9285 86,479 D ( 4 ) Common Stock, $0.001 par value ( 1 ) 04/26/2021 A 1,747 A $ 14.9009 88,226 D ( 4 ) Non-Voting Common Stock, $0.001 par value ( 1 ) 04/23/2021 C 152,176 A 152,176 D ( 4 ) Non-Voting Common Stock, $0.001 par value ( 1 ) 04/23/2021 C 134,515 A 286,691 D ( 4 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Series A Convertible Preferred Stock ( 5 ) 04/23/2021 C 115,293 ( 6 ) ( 5 ) ( 5 ) Common Stock, $0.001 par value 115,293 ( 5 ) 832,261 D ( 2 ) Series A Convertible Preferred Stock ( 5 ) 04/23/2021 C 832,261 ( 6 ) ( 5 ) ( 5 ) Non-Voting Common Stock, $0.001 par value 832,261 ( 5 ) 0 D ( 2 ) Series B Convertible Preferred Stock ( 5 ) 04/23/2021 C 1,068,554 ( 6 ) ( 5 ) ( 5 ) Non-Voting Common Stock, $0.001 par value 1,068,554 ( 5 ) 0 D ( 2 ) Series A Convertible Preferred Stock ( 5 ) 04/23/2021 C 84,350 ( 6 ) ( 5 ) ( 5 ) Common Stock, $0.001 par value 84,350 ( 5 ) 553,359 D ( 3 ) Series A Convertible Preferred Stock ( 5 ) 04/23/2021 C 553,359 ( 6 ) ( 5 ) ( 5 ) Non-Voting Common Stock, $0.001 par value 553,359 ( 5 ) 0 D ( 3 ) Series B Convertible Preferred Stock ( 5 ) 04/23/2021 C 837,397 ( 6 ) ( 5 ) ( 5 ) Non-Voting Common Stock, $0.001 par value 837,397 ( 5 ) 0 D ( 3 ) Series A Convertible Preferred Stock ( 5 ) 04/23/2021 C 17,390 ( 6 ) ( 5 ) ( 5 ) Common Stock, $0.001 par value 17,390 ( 5 ) 152,176 D ( 4 ) Series A Convertible Preferred Stock ( 5 ) 04/23/2021 C 152,176 ( 6 ) ( 5 ) ( 5 ) Non-Voting Common Stock, $0.001 par value 152,176 ( 5 ) 0 D ( 4 ) Series B Convertible Preferred Stock ( 5 ) 04/23/2021 C 134,515 ( 6 ) ( 5 ) ( 5 ) Non-Voting Common Stock, $0.001 par value 134,515 ( 5 ) 0 D ( 4 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other BVF PARTNERS L P/IL 44 MONTGOMERY STREET 40TH FLOOR SAN FRANCISCO, CA94104 X See Remarks BIOTECHNOLOGY VALUE FUND L P 44 MONTGOMERY STREET 40TH FLOOR SAN FRANCISCO, CA94104 See Explanation of Responses BVF I GP LLC 44 MONTGOMERY ST., 40TH FLOOR SAN FRANCISCO, CA94104 See Explanation of Responses BIOTECHNOLOGY VALUE FUND II LP 44 MONTGOMERY STREET 40TH FLOOR SAN FRANCISCO, CA94104 See Explanation of Responses BVF II GP LLC 44 MONTGOMERY ST., 40TH FLOOR SAN FRANCISCO, CA94104 See Explanation of Responses Biotechnology Value Trading Fund OS LP P.O. BOX 309 UGLAND HOUSE GRAND CAYMAN, E9KY1-1104 See Explanation of Responses BVF Partners OS Ltd. P.O. BOX 309 UGLAND HOUSE GRAND CAYMAN, E9KY1-1104 See Explanation of Responses BVF GP HOLDINGS LLC 44 MONTGOMERY ST., 40TH FLOOR SAN FRANCISCO, CA94104 See Explanation of Responses BVF INC/IL 44 MONTGOMERY STREET 40TH FLOOR SAN FRANCISCO, CA94104 See Explanation of Responses LAMPERT MARK N 44 MONTGOMERY STREET 40TH FLOOR SAN FRANCISCO, CA94104 See Explanation of Responses Signatures BVF Partners L.P., By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President 04/27/2021 Signature of Reporting Person Date Biotechnology Value Fund, L.P., By: BVF Partners L.P., its investment manager, By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President 04/27/2021 Signature of Reporting Person Date BVF I GP LLC, By: BVF GP HOLDINGS LLC, its sole member, By: /s/ Mark N. Lampert, Chief Executive Officer 04/27/2021 Signature of Reporting Person Date Biotechnology Value Fund II, L.P., By: BVF Partners L.P., its investment manager, By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President 04/27/2021 Signature of Reporting Person Date BVF II GP LLC, By: BVF GP HOLDINGS LLC, its sole member, By: /s/ Mark N. Lampert, Chief Executive Officer 04/27/2021 Signature of Reporting Person Date BVF Partners OS Ltd., By: BVF Partners L.P., its sole member, By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President 04/27/2021 Signature of Reporting Person Date Biotechnology Value Trading Fund OS LP, By: BVF Partners L.P., its investment manager, BVF Inc., its general partner, By: /s/ Mark N. Lampert, President 04/27/2021 Signature of Reporting Person Date BVF GP Holdings LLC, By: /s/ Mark N. Lampert, Chief Executive Officer 04/27/2021 Signature of Reporting Person Date BVF Inc., By: /s/ Mark N. Lampert, President 04/27/2021 Signature of Reporting Person Date /s/ Mark N. Lampert 04/27/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )This Form 4 is filed jointly by Biotechnology Value Fund, L.P. ("BVF"), Biotechnology Value Fund II, L.P. ("BVF2"), Biotechnology Value Trading Fund OS LP ("Trading Fund OS"), BVF Partners OS Ltd. ("Partners OS"), BVF I GP LLC ("BVF GP"), BVF II GP LLC ("BVF2 GP"), BVF GP Holdings LLC ("BVF GPH"), BVF Partners L.P. ("Partners"), BVF Inc. and Mark N. Lampert (collectively, the "Reporting Persons"). Each of the Reporting Persons is a member of a Section 13(d) group. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein except to the extent of his or its pecuniary interest therein. ( 2 )Securities owned directly by BVF. As the general partner of BVF, BVF GP may be deemed to beneficially own the securities owned directly by BVF. As the sole member of BVF GP, BVF GPH may be deemed to beneficially own securities owned directly by BVF. As the investment manager of BVF, Partners may be deemed to beneficially own the securities owned directly by BVF. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by BVF. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by BVF. ( 3 )Securities owned directly by BVF2. As the general partner of BVF2, BVF2 GP may be deemed to beneficially own the securities owned directly by BVF2. As the sole member of BVF2 GP, BVF GPH may be deemed to beneficially own securities owned directly by BVF2. As the investment manager of BVF2, Partners may be deemed to beneficially own the securities owned directly by BVF2. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by BVF2. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by BVF2. ( 4 )Securities owned directly by Trading Fund OS. As the general partner of Trading Fund OS, Partners OS may be deemed to beneficially own the securities owned directly by Trading Fund OS. As the investment manager of Trading Fund OS and the sole member of Partners OS, Partners may be deemed to beneficially own the securities owned directly by Trading Fund OS. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by Trading Fund OS. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by Trading Fund OS. ( 5 )Shares of Series A Convertible Preferred Stock and Series B Convertible Preferred Stock (together with the Series A Convertible Preferred Stock, the "Preferred Stock") were convertible at any time, at the holder's election and had no expiration date. Immediately prior to the closing of the Issuer's initial public offering ("IPO"), the Issuer issued shares of its non-voting common stock in exchange for outstanding shares of its Preferred Stock, in an amount such that shares held by such holder, including any shares purchased in the IPO and shares of common stock issued upon the conversion of the Preferred Stock, would result in such holder beneficially owning not more than 9.99% of the Issuer's common stock as of immediately following the closing of the IPO. ( 6 )Reflects the Preferred Stock on an as-converted basis of one-for-1.0799.

Remarks: For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, Partners may be deemed to be a director by deputization of the Issuer due to a member of Partners, Gorjan Hrustanovic, serving on the Board of Directors of the Issuer, and his agreement to transfer the economic benefit, if any, received upon the sale of the shares issuable upon exercise of the securities reported owned herein to Partners.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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