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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1. Name and Address of Reporting Person * Warthen Wayne B   2. Issuer Name and Ticker or Trading Symbol LoopNet, Inc. [LOOP] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chief Technology Officer & SVP (Last) (First) (Middle) C/O LOOPNET, INC., 2100 E. ROUTE, SUITE 200 3. Date of Earliest Transaction (Month/Day/Year) 04/30/2012 (Street) GLENDORA, CA 91740 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 04/30/2012   D   141,589 D (1) 0 D   Common Stock 04/30/2012   D   105,445 D (2) 0 I Wayne B. Warthern and Monica L. Warthern Trust Common Stock 04/30/2012   D   75,000 D (3) 0 D

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

Stock Option (Right to Buy)

$ 11.06

04/30/2012

D

1,251

(4)

01/08/2015

Common Stock

1,251

$ 0

0

D

Stock Option (Right to Buy)

$ 9.97

04/30/2012

D

150,000

(5)

02/10/2017

Common Stock

150,000

$ 0

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Warthen Wayne B C/O LOOPNET, INC. 2100 E. ROUTE, SUITE 200 GLENDORA, CA 91740			Chief Technology Officer & SVP

Signatures

/s/ Maria T. Valles, as Attorney-in-Fact		04/30/2012
**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)	Disposed of pursuant to a merger agreement, dated April 27, 2011, as amended, between the issuer, CoStar Group, Inc. ("Parent") and Lonestar Acquisition Sub, Inc. (the "Merger Agreement") in exchange for a unit consisting of (i) $16.50 in cash without interest and (ii) 0.03702 shares of the Parent Common Stock per share (the "Merger Consideration").
(2)	Disposed of pursuant to the Merger Agreement in exchange for the Merger Consideration.
(3)	Disposed of pursuant to the Merger Agreement. The securities disposed were restricted stock units granted on February 11, 2010, that were subject to performance-based vesting, the conditions for which were not met as of the time of the merger. Pursuant to the Merger Agreement, the vesting of all such securities fully accelerated, and two thirds of such restricted stock units were cancelled in exchange for the Merger Consideration, and one third of such restricted stock units were cancelled in exchange for 6,758 shares of Parent common stock.
(4)	Disposed of pursuant to the Merger Agreement. This option provided for a vesting of 1/48th per month beginning on February 9, 2008. Pursuant to the Merger Agreement, to the extent unvested, the vesting of the option was fully accelerated, and the options were cancelled in the merger in exchange for the Merger Consideration, less the exercise price of the option.
(5)	Disposed of pursuant to the Merger Agreement. This option was granted on February 11, 2010, and was subject to performance-based vesting, the conditions for which were not met as of the time of the merger. Pursuant to the Merger Agreement, the vesting of all such options fully accelerated, and two thirds of such options were cancelled in exchange for the Merger Consideration, less the exercise price of the option, and one third of such options were cancelled in exchange for 6,467 shares of Parent common stock.

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