Exhibit 99.1

Contact Information:

LOOPNET, INC. ANNOUNCES FIRST QUARTER 2012

FINANCIAL RESULTS

SAN FRANCISCO, CALIF. – April 25, 2012 – LoopNet, Inc. (NASDAQ: LOOP), today announced financial results for the first quarter ended March 31, 2012.

LoopNet’s revenue for the first quarter of 2012 was $22.9 million, compared to $20.7 million in the first quarter of 2011. Net income applicable to common stockholders for the first quarter of 2012 was $2.4 million or $0.05 per diluted share, compared to net income applicable to common stockholders of $1.8 million or $0.04 per diluted share in the first quarter of 2011. Non-GAAP net income, which excludes stock-based compensation, merger related costs and amortization of acquired intangible assets, for the first quarter of 2012 was $4.3 million or $0.10 per diluted share, compared to $4.0 million or $0.10 per diluted share in the first quarter of 2011.

LoopNet’s Adjusted EBITDA (earnings before net interest and other income (expense), income taxes, depreciation, amortization, stock-based compensation and merger related costs) for the first quarter of 2012 was $7.5 million, compared to $7.0 million in the first quarter of 2011.

Key operating metrics and business highlights from the first quarter of 2012 include:

Balance Sheet and Liquidity

As of March 31, 2012, LoopNet had $118.5 million of cash, cash equivalents and short-term investments and no debt.

Pending Merger Transaction

As disclosed on April 17, 2012, LoopNet and CoStar Group, Inc. (“CoStar”) announced that they have reached agreement on a mutually acceptable consent order with the staff of the Federal Trade Commission (the “FTC”). The consent order is subject to review and approval by the Commissioners of the FTC and if approved by the Commissioners, it would clear the way for the merger (the “Merger”) of LoopNet and CoStar that was previously announced on April 27, 2011. LoopNet and CoStar are not providing details of the consent order pending this Commission review and approval. Completion of the Merger remains subject to the expiration or termination of the waiting period imposed by the Hart-Scott-Rodino Act, which would occur upon the approval of the FTC Commissioners, and other customary closing conditions.

As of the date hereof, LoopNet and CoStar have not received the approval by the Commissioners of the FTC of the consent order. However, LoopNet and CoStar remain hopeful that they will receive such approval and be in a position to close the Merger by April 30, 2012. If that does not occur, the Merger Agreement dated as of April 27, 2011, as amended, does not terminate automatically after April 30, 2012 unless either LoopNet or CoStar exercises an affirmative election to terminate it.

Use of Non-GAAP Financial Measures

This press release includes discussions of Adjusted EBITDA, non-GAAP net income and non-GAAP net income per share, which are non-GAAP financial measures provided as a complement to results provided in accordance with accounting principles generally accepted in the United States of America (“GAAP”). The term “Adjusted EBITDA” refers to a financial measure that we define as earnings before income taxes, depreciation, amortization, net interest and other income (expense), stock-based compensation and merger related costs. The term “non-GAAP net income” refers to a financial measure that we define as net income before stock-based compensation, merger related costs and amortization of acquired intangible assets. Non-GAAP net income is also provided on a per share basis, using shares outstanding at the relevant period of measurement. Adjusted EBITDA, non-GAAP net income and non-GAAP net income per share are not substitutes for measures determined in accordance with GAAP, and may not be comparable to Adjusted EBITDA, non-GAAP net income and non-GAAP net income per share as reported by other companies. We believe Adjusted EBITDA to be relevant and useful information to our investors as this measure is an integral part of our internal management reporting and planning process and is the primary measure used by our management to evaluate the operating performance of our business. The components of Adjusted EBITDA include the key revenue and expense items for which our operating managers are responsible and upon which we evaluate their performance, and we also use Adjusted EBITDA for planning purposes and in presentations to our board of directors. We believe non-GAAP net income and non-GAAP net income per share to be relevant and useful information to our investors as they provide meaningful insight into our performance while excluding infrequent and non-recurring items that may not be considered directly related to our on-going business operations. We believe that non-GAAP net income and non-GAAP net income per share are also used by companies and investors to evaluate comparable performance in the online marketplace and platform industry. We also believe that Adjusted EBITDA, non-GAAP net income and non-GAAP net income per share allow for a more accurate comparison of our operating results over historical periods. A limitation of Adjusted EBITDA, non-GAAP net income and non-GAAP net income per share is that they do not include all items that impact our net income for the period. Management compensates for this limitation by also relying on the comparable GAAP financial measure of net income, which includes the items that are excluded from Adjusted EBITDA, non-GAAP net income and non-GAAP net income per share. Management believes that these non-GAAP measures should be considered as a complement to, and not as a substitute for, or superior to, the corresponding measures calculated in accordance with GAAP. A reconciliation of these non-GAAP measures to GAAP is provided in the attached tables.

About LoopNet, Inc.

LoopNet operates the most heavily trafficked commercial real estate marketplace online with more than 5 million registered members and 2.8 million unique monthly visitors, as reported by Google Analytics.

The LoopNet marketplace covers all commercial property categories, including office, industrial, retail, multifamily (apartment properties for sale), hotel, land, specialty properties, investment properties and businesses for sale. LoopNet customers include virtually all of the top commercial real estate firms in the U.S., including Apartment Realty Advisors, Avison Young, Cassidy Turley, CB Richard Ellis, Coldwell Banker Commercial, Colliers International, Cushman & Wakefield, Jones Lang LaSalle, Lee & Associates, Lincoln Property Company, NAI Global, Newmark Knight Frank, The Shopping Center Group and Sperry Van Ness.

Forward Looking Statements

This release contains forward-looking statements regarding our financial results and the Merger. These statements are based on current information and expectations that are inherently subject to change and involve a number of risks and uncertainties. Actual events or results might differ materially from those in any forward-looking statement due to various factors. The following factors related to the Merger, among others, could cause or contribute to such differences: the possibility that the Commissioners of the FTC will not approve the consent order in a timely manner or at all; the possibility that the FTC will request additional extensions to the waiting period imposed by the HSR Act; the possibility that conditions, divestitures or changes relating to the operations or assets of LoopNet and CoStar will be required to obtain required governmental clearances or approvals, including, but not limited to, clearance or approval by the FTC; the possibility that the Merger does not close, including, but not limited to, due to the failure to obtain governmental clearances or approvals; the risk that expected cost savings or other synergies from the Merger may not be fully realized or may take longer to realize than expected; the risk that the businesses of LoopNet and CoStar may not be combined successfully or in a timely and cost-efficient manner; the risk that business disruption relating to the Merger may be greater than expected; and the failure by CoStar to obtain any required financing on favorable terms.

In addition, the following factors, among others, could also cause results to differ materially from those anticipated in the forward-looking statements: economic events or trends in the commercial real estate market or in general; the effects of recent economic and consumer confidence trends on global and domestic financial markets, including credit available to real estate purchasers; our ability to continue to attract and retain new registered members, convert registered members into premium members and retain such premium members; seasonality; our ability to manage our growth; our ability to successfully integrate the technologies, operations and personnel of acquired businesses in a timely manner; our ability to obtain the expected strategic and financial benefits from acquisitions; our ability to introduce new or upgraded products or services and customer acceptance of such services; and our ability to obtain or retain listings from commercial real estate brokers, agents and property owners.

Additional information concerning factors that could cause actual events or results to differ materially from those in any forward looking statement are contained in our Annual Report on Form 10-K and Quarterly Reports on Form 10-Q filed with the Securities and Exchange Commission (“SEC”), and other SEC filings made by us. Copies of filings made by us with the SEC are available on the SEC’s website or at http://investor.loopnet.com/sec.cfm. LoopNet does not intend to update the forward-looking statements included in this press release which are based on information available to us as of the date of this release.

LOOPNET, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

(In thousands, except share data)

LOOPNET, INC.

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(In thousands, except per share data)

(unaudited)

LOOPNET, INC.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(In thousands)

(unaudited)

LOOPNET, INC.

Reconciliation of GAAP Net Income to Adjusted EBITDA

(In thousands, except per share data)

Reconciliation of GAAP Net Income to Non-GAAP Net Income

(In thousands, except per share data)