Activist hedge fund Sachem Head Capital Management has secured a board seat at Six Flags Entertainment, intensifying investor influence over the struggling theme park operator following months of pressure to improve performance, according to a report by Reuters.

Six Flags announced the appointment of Jonathan Brudnick, a partner at Sachem Head, to its board of directors, expanding the board to 13 members. Brudnick will also join the nominating and corporate governance committee, signalling a greater activist presence in the company’s strategic oversight.

Sachem Head, which now holds nearly 10% of Six Flags, began building its stake in the second quarter amid a sharp decline in the company’s share price – down more than 55% this year to $21.26 – after poor weather dampened summer attendance. The $2.1bn market-cap operator, newly formed from the merger of Six Flags and Cedar Fair, has drawn growing scrutiny from activist investors seeking a turnaround.

Rival hedge fund Land & Buildings, which owns about 2%, has renewed its call for Six Flags to spin off its real estate holdings into a REIT to unlock value, an idea it first proposed in 2022.

For Sachem Head, the Six Flags appointment marks its second board win in under a month, following the addition of founder Scott Ferguson to the Performance Food Group board in September.