(Reuters) -Bain Capital Private Equity has proposed to acquire the remaining shares of surgical facility operator Surgery Partners it does not already own for $25.75 apiece, a filing showed on Tuesday.

Bain Capital has a 39% stake in the company, according to LSEG data.

Shares of Surgery Partners rose 17% in early trading.

The proposed offer represents a 21.2% premium to the company's last closing price.

The proposed premium is probably insufficient, which could invite competing higher bids, a process made more likely by the fact that some strategic and financial buyers have already taken a hard look at the company, Benchmark analyst Bill Sutherland said.

Bloomberg News previously reported that TPG Inc and UnitedHealth Group were among suitors seeking to buy the company.

The report also said that Surgery Partners was drawing interest from other private equity firms and strategic bidders.

The proposal was submitted after Surgery Partners evaluated strategic alternatives involving multiple financial and strategic parties but did not result in a transaction, Bain Capital said in a letter dated Monday.

"We have reflected on these events and current investor sentiment and have concluded that our proposal is in the best interests of the company and its stockholders," Bain Capital said in the letter.

Bain added that it is only interested in acquiring the shares it doesn't already own and has no intention of selling the shares it currently holds.

Bain Capital and Surgery Partners did not immediately respond to a Reuters requests for comment.