Ownership Submission
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 OF SECURITIES

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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(Print or Type Responses)
1. Name and Address of Reporting Person *
ELMS STEVE
  2. Issuer Name and Ticker or Trading Symbol
AMBIT BIOSCIENCES CORP [AMBI]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
C/O AMBIT BIOSCIENCES CORPORATION, 11080 ROSELLE STREET
3. Date of Earliest Transaction (Month/Day/Year)
05/21/2013
(Street)

SAN DIEGO, CA 92121
4. If Amendment, Date Original Filed(Month/Day/Year)
6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ 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 (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 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 05/21/2013   C   28,901 A (1) 29,120 I See Footnote (2)
Common Stock 05/21/2013   C   57,448 A (3) 86,568 I See Footnote (2)
Common Stock 05/21/2013   C   227,801 A (4) 314,369 I See Footnote (2)
Common Stock 05/21/2013   C   456,393 A (5) 770,762 I See Footnote (2)
Common Stock 05/21/2013   C   352,047 A (6) 1,122,809 I See Footnote (2)
Common Stock 05/21/2013   P   423,635 (8) A $ 8 1,546,444 I See Footnote (2)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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 (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 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
(Month/Day/Year)
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 B Preferred Stock (1) 05/21/2013   C     693,641   (1)   (1) Common Stock 28,901 $ 0 0 I See Footnote (2)
Series C Preferred Stock (3) 05/21/2013   C     1,378,747   (3)   (3) Common Stock 57,448 $ 0 0 I See Footnote (2)
Series D Preferred Stock (4) 05/21/2013   C     2,474,300   (4)   (4) Common Stock 227,801 $ 0 0 I See Footnote (2)
Series D-2 Preferred Stock (5) 05/21/2013   C     10,953,433   (5)   (5) Common Stock 456,393 $ 0 0 I See Footnote (2)
Series E Preferred Stock (6) 05/21/2013   C     8,449,121   (6)   (6) Common Stock 352,047 $ 0 0 I See Footnote (2)
Stock Option (right to buy) $ 6.66 05/21/2013   A     7,085   (7) 05/20/2023 Common Stock 7,085 $ 0 7,085 D (9)  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
ELMS STEVE
C/O AMBIT BIOSCIENCES CORPORATION
11080 ROSELLE STREET
SAN DIEGO, CA 92121
  X      

Signatures

 /s/ Steve Elms   05/21/2013
**Signature of Reporting Person Date

Explanation of Responses:

* 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).
(1) Upon the closing of the Issuer's initial public offering, every 24 shares of Series B Preferred Stock automatically converted into 1 share of Common Stock for no additional consideration and had no expiration date.
(2) The reportable securities are held directly by Perseus-Soros Biopharmaceutical Fund, L.P., or PSBF, and are indirectly held by Perseus-Soros Partners, LLC or PSPGP, as general partner of PSBF, Aisling Capital LLC, or Aisling Capital, as the managing member of PSPGP, and each of the individual managing members of Aisling Capital, including the Reporting Person. PSBF, PSPGP, Aisling Capital and the individual managing members of Aisling Capital, including the Reporting Person, share voting and dispositive power over the reportable securities directly held by PSBF. The Reporting Person serves as a director of the Issuer.
(3) Upon the closing of the Issuer's initial public offering, every 24 shares of Series C Preferred Stock automatically converted into 1 share of Common Stock for no additional consideration and had no expiration date.
(4) Upon the closing of the Issuer's initial public offering, every 10.86166 shares of Series D Preferred Stock automatically converted into 1 share of Common Stock for no additional consideration and had no expiration date. The conversion ratio was incorrectly stated in the Reporting Person's Form 3.
(5) Upon the closing of the Issuer's initial public offering, every 24 shares of Series D-2 Preferred Stock automatically converted into 1 share of Common Stock for no additional consideration and had no expiration date.
(6) Upon the closing of the Issuer's initial public offering, every 24 shares of Series E Preferred Stock automatically converted into 1 share of Common Stock for no additional consideration and had no expiration date.
(7) One-third of the shares will vest on the first, second and third year anniversaries of the date of grant, such that the stock option is fully vested on May 21, 2016, subject to the optionee's continuous service with the Issuer through such vesting date.
(8) The shares were purchased by PSBF in a private placement concurrent with the closing of the Issuers' initial public offering.
(9) These stock options are held by Mr. Elms for the benefit of Aisling Capital LLC. Mr. Elms disclaims beneficial ownership of these securities and this report is not an admission that he is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of his pecuniary interest therein.

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