Royal Capital Management LLC is calling for the ouster of WellPoint Inc. CEO Angela Braly in a letter to the health insurer, saying she has “failed miserably.”

“It is incumbent upon the board of directors to fulfill its fiduciary responsibility to shareholders by changing leadership,” Royal Capital said in the letter sent Wednesday.

The New York-based hedge fund had 837,800 shares of WellPoint, the second-biggest U.S. health insurer, as of June 30, according to data compiled by Bloomberg.

Braly, CEO since 2007, has been under fire since cutting the Indianapolis-based insurer’s full-year forecast last month after earnings missed analysts’ estimates for the second time in three quarters. WellPoint’s share price has declined 7 percent since she because chairman in March 2010, leading two other shareholders, investment fund Orbimed Advisors LLC and hedge fund Omega Advisors Inc., to criticize the management of the company.

“The market has spoken, as evidenced by WellPoint’s stock price,” Royal Capital partners Robert Medway and John Lancefield said in the letter. Braly “has failed miserably, shareholders have paid dearly and it is time to make a change. Leadership that demands excellence, accuracy and results is needed, and she simply does not fit the bill.”

The fund owned 0.26 percent of WellPoint’s outstanding shares as of June 30, according to data compiled by Bloomberg.

Kristin Binns, a WellPoint spokeswoman, didn’t respond to a message seeking comment.

WellPoint shares declined 1.4 percent Thursday, to close at $57.74 each. Shares have dropped 2.9 percent in the past 12 months. Minnetonka, Minn.-based UnitedHealth Group Inc., the only U.S. plan larger than WellPoint, has gained 20 percent in the same 12-month period and increased has 58 percent since Braly took on WellPoint’s chairmanship.

“We believe there is one, and only one, explanation for WellPoint’s underperformance: well-deserved investor antipathy toward Ms. Braly as a result of a regular cadence of managerial blunders that has plagued her term as CEO,” Medway and Lancefield said in the letter. “We, of course, cannot know what additional surprises and accompanying stock price sell-offs the year has in store if Ms. Braly is allowed to stay, but the recent guidance reduction augurs poorly.”

Medway and Lance blamed the 51-year-old Braly for what they called five years of underperformance, including reduced guidance, regulatory problems with Medicare products, political fights with Democratic politicians, and departing customers.

Lancefield declined to comment beyond the letter, saying that it spoke for itself.

WellPoint owns Blue Cross plans in 14 states and is the nation’s largest seller of health policies to individuals and small businesses. Both markets have been losing customers, and are expected to become less profitable because of new rules in the health-care law. Membership in WellPoint’s medical plans fell 2.3 percent, to 33.5 million, in the second quarter from a year earlier.

Last month, WellPoint announced the $4.9 billion purchase of Amerigroup Corp. to become biggest private provider of Medicaid plans to low-income customers.

Royal Capital is the latest investor to single out Braly for WellPoint’s disappointing performance.

“There’s a universal view that the CEO is the wrong CEO to lead the business,” said Leon Cooperman, founder of New York- based Omega Advisors Inc., in an interview last month. Cooperman’s hedge fund held 2.1 million WellPoint shares as of March.

Kuhn Tsai, an analyst at Orbimed Advisors in New York, which held 1.25 million shares in March, earlier this month also attributed the company’s poor performance to “management missteps.”

The Royal Capital investors also criticized the WellPoint board, saying that keeping Braly “will be viewed as inexplicable complacency in the face of abundant evidence that change is needed.” WellPoint’s board has been meeting with investors following the release of the company’s second-quarter results on July 25.

Investors “are understandably confused as to what process the board is undertaking,” they wrote.

Braly has the support of the board, lead director Jacquelyn Ward said in a statement released after the July 25 earnings report. The directors are “fully involved in the strategy WellPoint is pursuing and is supportive of the strategy and our management team,” Ward wrote in an e-mail.

Lenox Baker, a retired cardiac surgeon who has been on the board of the Indianapolis-based insurer for about a decade, said on Aug. 10 in a telephone interview that the board backed Braly, and the pressure to remove her was being driven by short-term investors.