CSGP · Costar Group, Inc. · Insider Trading

Average based on sales prices ranging from $29.57 to $29.99.

Each restricted stock unit represents a contingent right to receive one share of CoStar Group, Inc. common stock.

The restricted stock units vest in three equal installments on August 1, 2027, August 1, 2028 and August 1, 2029.

Each restricted stock unit represents a contingent right to receive one share of CoStar Group, Inc. common stock.

The restricted stock units vest in four equal installments on August 1, 2027, August 1, 2028, August 1, 2029, and August 1, 2030.

The restricted stock award vests in full on the earlier of either the first anniversary of the grant date or the date of the Company's 2027 Annual Meeting of Stockholders.

The restricted stock award vests in full on the earlier of either the first anniversary of the grant date or the date of the Company's 2027 Annual Meeting of Stockholders.

This amount includes shares that were inadvertently omitted from the insider's prior filing.

The restricted stock award vests in full on the earlier of either the first anniversary of the grant date or the date of the Company's 2027 Annual Meeting of Stockholders.

The restricted stock award vests in full on the earlier of either the first anniversary of the grant date or the date of the Company's 2027 Annual Meeting of Stockholders.

The restricted stock award vests in full on the earlier of either the first anniversary of the grant date or the date of the Company's 2027 Annual Meeting of Stockholders.

The restricted stock award vests in full on the earlier of either the first anniversary of the grant date or the date of the Company's 2027 Annual Meeting of Stockholders.

The restricted stock award vests in full on the earlier of either the first anniversary of the grant date or the date of the Company's 2027 Annual Meeting of Stockholders.

Average based on sales prices ranging from $35.68 to $36.00.

Average based on sales prices ranging from $34.67 to $35.67.

On March 13, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $43.63.

On March 13, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $43.63.

On March 13, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $43.63.

This amount reflects a correction due to administrative error.

On March 13, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $43.63.

On March 13, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $43.63.

Pursuant to the Management Stock Purchase Plan, all or a portion of the reporting person's annual cash incentive amount was converted to Deferred Stock Units (each equivalent to one share of common stock) at $46.34 per unit, and the Company awarded the reporting person Restricted Stock Units that vest in full after four years for an equal number of shares of common stock.

Pursuant to the Management Stock Purchase Plan, all or a portion of the reporting person's annual cash incentive amount was converted to Deferred Stock Units (each equivalent to one share of common stock) at $46.34 per unit, and the Company awarded the reporting person Restricted Stock Units that vest in full after four years for an equal number of shares of common stock.

Pursuant to the Management Stock Purchase Plan, all or a portion of the reporting person's annual cash incentive amount was converted to Deferred Stock Units (each equivalent to one share of common stock) at $46.34 per unit, and the Company awarded the reporting person Restricted Stock Units that vest in full after four years for an equal number of shares of common stock.

Pursuant to the Management Stock Purchase Plan, all or a portion of the reporting person's annual cash incentive amount was converted to Deferred Stock Units (each equivalent to one share of common stock) at $46.34 per unit, and the Company awarded the reporting person Restricted Stock Units that vest in full after four years for an equal number of shares of common stock.

Pursuant to the Management Stock Purchase Plan, all or a portion of the reporting person's annual cash incentive amount was converted to Deferred Stock Units (each equivalent to one share of common stock) at $46.34 per unit, and the Company awarded the reporting person Restricted Stock Units that vest in full after four years for an equal number of shares of common stock.

Average based on sales prices ranging from $45.26 to $45.38

This amount includes shares that were inadvertently omitted from the insider's prior filing.

On February 27, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $44.63.

On February 27, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $44.63.

Includes 142 shares acquired under the CoStar Group, Inc. Employee Stock Purchase Plan.

On February 27, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $44.63.

On February 27, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $44.63.

On February 27, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $44.63.

On February 27, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $44.63.

Includes 157 shares acquired under the CoStar Group, Inc. Employee Stock Purchase Plan.

On February 27, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $44.63.

On February 27, 2026, the last preceding business day, the closing price of the Company's common stock on Nasdaq was $44.63.

Each restricted stock unit represents a contingent right to receive one share of CoStar Group, Inc. common stock.

The restricted stock units vest in three equal installments on March 1, 2027, March 1, 2028 and March 1, 2029.

Each restricted stock unit represents a contingent right to receive one share of CoStar Group, Inc. common stock.

The restricted stock units vest in three equal installments on March 1, 2027, March 1, 2028 and March 1, 2029.

Each restricted stock unit represents a contingent right to receive one share of CoStar Group, Inc. common stock.

The restricted stock units vest in three equal installments on March 1, 2027, March 1, 2028 and March 1, 2029.

Each restricted stock unit represents a contingent right to receive one share of CoStar Group, Inc. common stock.

The restricted stock units vest in four equal installments on March 1, 2027, March 1, 2028, March 1, 2029, and March 1, 2030.

Each restricted stock unit represents a contingent right to receive one share of CoStar Group, Inc. common stock.

The restricted stock units vest in three equal installments on March 1, 2027, March 1, 2028 and March 1, 2029.

Average based on sales prices ranging from $44.08 to $44.74.

Each restricted stock unit represents a contingent right to receive one share of CoStar Group, Inc. common stock.

The restricted stock units vest in three equal installments on March 1, 2027, March 1, 2028 and March 1, 2029.

Each restricted stock unit represents a contingent right to receive one share of CoStar Group, Inc. common stock.

The restricted stock units vest in three equal installments on March 1, 2027, March 1, 2028 and March 1, 2029.

Each restricted stock unit represents a contingent right to receive one share of CoStar Group, Inc. common stock.

The restricted stock units vest in three equal installments on March 1, 2027, March 1, 2028 and March 1, 2029.

On February 19, 2026, the closing price of the Company's Common Stock on Nasdaq was $49.07.

Shares forfeited from February 14, 2023 performance restricted stock grant upon certification of actual achievement of the performance goal by the Compensation Committee.