NEW YORK, Oct 21 (Reuters) - Activist investor Jana

Partners has teamed up with football star Travis Kelce to push

Six Flags Entertainment ( FUN ) to improve its marketing and

customer experiences, the investor said, after disclosing a 9%

stake in the company.

Jana Partners' Scott Ostfeld announced the position at the 13D

Monitor Active Passive-Investment Summit in New York on Tuesday,

saying he has partnered with Kelce and two business industry

executives to pressure the company to improve its performance.

Shares of Six Flags shot up 17% on Tuesday after Ostfeld

spoke to $25.63.

The stock is down 58% since it completed a merger with

fellow theme park operator Cedar Fair in July 2024.

The stock has a market capitalization of roughly $2.6

billion, and has struggled this year as rainy weather at the

start of the summer kept visitors away from its parks.

Kelce, a star tight end for the NFL's Kansas City Chiefs, is

a popular podcast host who recently became engaged to singer

Taylor Swift. He has described himself as a theme park

"superfan" and has often visited the company's parks.

Jana is joining a field of activists approaching Six Flags

with ideas on how to improve the share price.

On Friday, the company said it added an executive from

activist hedge fund Sachem Head Capital Management to its board.

Consumer executive Glenn Murphy and technology executive

Dave Habiger are also working with Jana and could, along with

Kelce, serve as potential board nominees.