(Reuters) -A Skechers USA ( SKX ) shareholder has sued the footwear maker for more details about its $9.4 billion buyout by private equity firm 3G Capital, saying the decision by Skechers' founder and controlling shareholder to sell raises "red flags."

According to a complaint filed on Thursday in Los Angeles federal court, founder Robert Greenberg and his family, who hold about 60% of Skechers' voting power, appear to have "controlled the sales process to a single bidder and deprived the minority stockholders of any legitimate bidding process."

Florida-based Key West Police Officers & Firefighters Retirement Plan said the buyout should not close until Skechers makes required disclosures with the U.S. Securities and Exchange Commission to help shareholders decide if the terms are fair.

The complaint cited a Reuters article in which Needham analyst Tom Nikic called the buyout "very surprising" because Skechers was considered a family business, and sources said the Greenbergs eschewed an auction because of their long ties to 3G.

Known for comfort-first sneakers, Skechers is the world's third-largest footwear maker.

Skechers spokeswoman Jennifer Clay declined to comment on Friday, saying the Manhattan Beach, California-based company does not discuss pending litigation.

The vast majority of large U.S. corporate mergers are challenged in court. Lawsuits seeking greater disclosures often end with defendants paying legal fees to plaintiffs' lawyers, and plaintiffs recovering nominal payouts or nothing.

According to a regulatory filing, Greenberg, 85, could collect more than $1 billion from the buyout, which is scheduled to close in the third quarter.

The buyout values Skechers at $63 per share in cash, 20% below its 52-week high of $78.82 set on January 30.

Like other footwear makers including Nike ( NKE ), Skechers faces pressure from U.S. President Donald Trump's tariffs.

Many Skechers' products come from China, and the company withdrew its full-year financial guidance in April.

Brazil-based 3G is known for stringent cost-cutting, including at such companies as Anheuser-Busch InBev and Kraft Heinz ( KHC ).

The case is Key West Police Officers & Firefighters Retirement Plan v Skechers USA Inc ( SKX ) et al, U.S. District Court, Central District of California, No. 25-04863.