Brendan McDermid/Reuters

WellPoint’s chief executive, Angela F. Braly, who orchestrated several big deals in recent months, abruptly resigned on Tuesday as a result of mounting pressure from shareholders.

Under the guidance of Ms. Braly, WellPoint has been one of the industry’s most active deal makers.

In a bid to expand WellPoint’s business, Ms. Braly, who assumed the top spot in 2007, has pursued several big transactions in the last year, including the $800 million purchase of CareMore and the more recent takeover of 1-800-Contacts. In July, Ms. Braly also signed her largest transaction, the $4.9 billion acquisition of Amerigroup, as WellPoint looked to take advantage of the expansion of health care coverage under President Obama.

But it was not enough to appease shareholders, frustrated by WellPoint’s sagging stock price and weak financial performance. In the most recent quarter, the insurance company’s profit fell about 8 percent, to $643.6 million, from the period a year earlier. Revenue also came in a below analysts’ expectations.

Even as the company shakes up its management, the board remains committed to its deal-making efforts.

“Our Board continues to believe that time will prove the wisdom of potentially transformative actions taken under Angela’s leadership, from the sale of the pharmacy benefit management business to Express Scripts to the recent and proposed acquisitions of CareMore, 1-800-CONTACTS and Amerigroup,” Jackie M. Ward, the board’s lead director, said in a statement. “But now is the right time for a leadership change.”

WellPoint said the company’s general counsel, John Cannon, will serve as interim chief as the board’s search committee examines internal and external candidates. The company also named Ms. Ward to the role of nonexecutive chair. On Tuesday, the company said Mr. Cannon would now “lead our most important initiative, which is the completion of the Amerigroup transaction.”