SEC FORM 3

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0104
Estimated average burden
hours per response:			0.5

1. Name and Address of Reporting Person^*

Burow Kristina

(Last)

(First)

(Middle)

8725 WEST HIGGINS ROAD, SUITE 290

(Street)

CHICAGO

60631

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
05/08/2013

3. Issuer Name and Ticker or Trading Symbol
Receptos, Inc. [ RCPT ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	10% Owner
	Officer (give title below)	Other (specify below)

5. If Amendment, Date of 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

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	13,333	D
Common Stock	114,285	I	See Footnotes⁽²⁾⁽³⁾⁽⁴⁾

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Series A Preferred Stock	⁽¹⁾	⁽¹⁾	Common Stock	129,755	$5.25	I	See Footnotes⁽²⁾⁽³⁾⁽⁴⁾
Series A Preferred Stock	⁽¹⁾	⁽¹⁾	Common Stock	1,022,283	$5.25	I	See Footnotes⁽²⁾⁽³⁾⁽⁴⁾
Series B Preferred Stock	⁽¹⁾	⁽¹⁾	Common Stock	680,323	$7.73	I	See Footnotes⁽²⁾⁽³⁾⁽⁴⁾

Explanation of Responses:

1. The Series A Preferred Stock and the Series B Preferred Stock have no expiration date and are convertible at any time at the option of the holder. The Series A Preferred Stock and the Series B Preferred Stock will convert upon the closing of the Issuer's initial public offering at a conversion ratio of 1 share of Common Stock for every 7.5 shares of Series A Preferred Stock and Series B Preferred Stock, for no additional consideration.

2. Beneficial ownership consists of: (i) 114,285 shares of common stock held by ARCH Venture Fund VII, L.P. ("ARCH Fund VII"); (ii) an aggregate of 129,755 shares of common stock issuable upon conversion of shares of Series A preferred stock held by ARCH Venture Fund VI, L.P. ("ARCH Fund VI"); and (iii) 1,702,606 shares of common stock issuable upon conversion of shares of Series A preferred stock and Series B preferred stock held by ARCH Fund VII. The sole general partner of ARCH Fund VI is ARCH Venture Partners VI, L.P. ("ARCH Partners VI"), which may be deemed to beneficially own the shares held by ARCH Fund VI.

3. The sole general partner of ARCH Partners VI is ARCH Venture Partners VI, LLC ("ARCH VI LLC"), which may be deemed to beneficially own the shares held by ARCH Fund VI. ARCH Partners VI and ARCH VI LLC disclaim beneficial ownership of such shares, except to the extent of any pecuniary interest therein. The sole general partner of ARCH Fund VII is ARCH Venture Partners VII, L.P. ("ARCH Partners VII"), which may be deemed to be the beneficial owner of the shares held by ARCH Fund VII. The sole general partner of ARCH Partners VII is ARCH Venture Partners VII, LLC ("ARCH VII LLC"), which may be deemed to be the beneficial owner of the shares held by ARCH Fund VII. ARCH Partners VII and ARCH VII LLC disclaim beneficial ownership of such shares, except to the extent of any pecuniary interest therein.

4. The managing directors of ARCH VI LLC and ARCH VII LLC are Keith Crandell, Clinton Bybee and Robert Nelsen, and they may be deemed to beneficially own the shares held by ARCH Fund VI and ARCH Fund VII. Messrs. Crandell, Bybee and Nelsen disclaim beneficial ownership of such shares, except to the extent of any pecuniary interest therein. Director Kristina Burow owns an interest in ARCH Partners VI and ARCH Partners VII but does not have voting or investment control over the shares held by ARCH Fund VI or ARCH Fund VII and disclaims beneficial ownership of such shares, except to the extent of any pecuniary interest therein.

Remarks:

Exhibit List: Exhibit 24 - Power of Attorney

	/s/ Kristina Burow	05/08/2013
	** Signature of Reporting Person	Date
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 5 (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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.