An E.l.f. beauty look from the Christian Siriano show.

E.l.f. Beauty is feeling the pressure of an activist investor.

New York-based hedge fund Marathon Partners Equity Management, which has a near 9 percent stake in the publicly listed discount cosmetics company, wrote to the board Friday, urging an overhaul of the firm’s operating strategy, corporate governance practices and executive compensation.

“It is unfortunate that we have not been able to find common ground with the E.l.f. team and board over the past six months,” said Mario Cibelli, head of Marathon Partners. “Senior leadership and the board have lost sight of the obligations and responsibilities that come with accepting new investors and public company ownership.”

The investor detailed that since E.l.f. went public in September 2016, its share price has fallen by 51 percent and stressed that the firm needed to optimize its expense structure and refocus on profitable growth in order to regain investor credibility and drive shareholder returns higher.

In order to do reduce operating expenses, all options must be considered, including difficult decisions related to personnel, compensation, office space requirements and E.l.f.-owned store count, it said.

Marathon Partners also questioned the amount of influence private equity firm TPG, which owns close to 30 percent of Oakland, Calif.-based E.l.f., has over the board, with a total of three representatives sitting on it.

To ease these concerns, it demanded a non-TPG designated director be appointed to the role of lead independent director and for the board to seek new, independent counsel to review the stockholders agreement. It also pushed for the role of chairman and chief executive officer to be split.

“The board has been overly accommodative to the interests of TPG on several levels, and this stance has harmed the independent public shareholders of E.l.f.,” Cibelli said in his letter.

It did, however, acknowledge that the board had attempted to address some of these issues of the past few months, namely adding a person not affiliated with TPG to the compensation committee.

The letter comes after E.l.f., which was founded in 2004, posted an 11 percent slide in third-quarter sales in November, while net income also fell, to $8.4 million from $9.6 million in the prior-year period.

Shares in E.l.f. rose 2.8 percent to $8.48 in midday trading.

Tarang Amin, chairman and chief executive of e.l.f. Beauty, said: “We have an active and ongoing dialogue with Marathon Partners and the firm’s views are well understood by our board and leadership team.  We continue to actively address a number of strategies to strengthen e.l.f. and build long-term stockholder value.”

A representatives for TPG did not immediately respond to request for comment.