Robert Mercer, co-chief executive officer of Renaissance Technologies LLC, was sued by household staff who said the fund manager didn’t pay overtime and docked wages for not replacing shampoo bottles or straightening pictures.

Mercer, whose Setauket, New York-based hedge fund had $20 billion in net assets in April, levied “demerits” of as much as $20 per infraction on workers at his home in Head of the Harbor, New York, according to a federal lawsuit filed July 10 in Central Islip, New York.

Workers lost part of their semi-annual bonuses for “failing to replace shampoos and other toiletries” when less than one-third of a bottle remained; “failing to properly close doors”; and “failing to leave extra towels in the bathroom,” according to the complaint. Other violations included “failing to level pictures; leaving cleaning items out” and “improperly counting beverages,” according to the complaint.

Renaissance Technologies, which employs dozens of math and physics doctorate-holders, is one of the largest quant funds, which use mathematical algorithms and computers to identify trades. Mercer is “one of the top-earning hedge fund managers,” according to the complaint.

Alba Aguilar, Luis Alzate and Carmen Rodriguez filed the suit on behalf of as many as 10 current and former employees of Owl’s Nest Inc., which hires Mercer’s domestic help, according to the complaint. The workers want back pay for overtime, recovery of lost bonus payments and other damages in a suit claiming violations of state and federal labor laws.

Jonathan Gasthalter, a spokesman for Renaissance at Sard Verbinnen & Co., didn’t have an immediate comment on the lawsuit.

The case is Aguilar v. Owl’s Nest Inc., 2:13-cv-3848, U.S. District Court, Eastern District of New York (Central Islip).