New York investor Simon Glick has bought a nearly 10 percent stake in Six Flags Inc., a move that followed Redskins owner Daniel Snyder's bid to take control of the amusement park company.

It is unclear what impact Glick's involvement will have on Snyder's effort to replace the firm's leaders with his own team.

Glick over the past three weeks has shelled out $64.4 million to acquire a 9.7 percent stake in Six Flags, placing him among the 10 largest Six Flags shareholders, filings with the Securities and Exchange Commission show.

Snyder is the firm's largest investor, with 11.7 percent. Other investors include Microsoft founder Bill Gates and Omaha investor Wallace Weitz's investment fund.

Glick began buying up shares on Aug. 19 -- just two days after Snyder said he planned to ask Six Flags shareholders to effectively turn the company over to him and his team, which includes outgoing ESPN programming executive Mark Shapiro and local home builder Dwight C. Schar. Snyder claims he can run the chain of 30 amusement parks better than its current management and has hinted he wants to use it as part of a larger entertainment enterprise.

The company, suffering from poor stock performance, a heavy debt load and a string of losses, yesterday announced it was selling its 109-acre AstroWorld theme park in Houston.

Snyder must persuade owners of at least 50 percent of Six Flags shares to go along with him if he wants to win the three board seats he is after.

In response, Six Flags management has asked shareholders to reject Snyder's request, according to SEC filings. The board also put the company up for sale, in an attempt to make Snyder buy the company outright or attract other bidders.

None of the major shareholders -- including Gates, Weitz and now Glick -- has stated an opinion publicly about Snyder's plans, although Gates last year did say he was dissatisfied with Six Flags' management.

Glick was out of town yesterday, said a woman who answered the phone at his Manhattan residence and said she was his daughter.

A Six Flags spokeswoman reached last night said she was not familiar with Glick.

Glick is no stranger to takeover battles. Last year, he was a major investor in a group led by Morgan Stanley that went head-to-head against a consortium led by Canadian developer Paul Reichman for control of Canary Wharf Group, a British real estate company that developed the Docklands area of offices, marinas and apartments in London's financial district.

Glick and his Six Flags investment partner, Seymour Pluchenik, filed yesterday under the name Diaco Investments. Pluchenik did not return a message left with a family member at his home.

In their filing yesterday, they said they may "in the future engage in discussions with management, the board of directors, other stockholders and other relevant parties concerning the business, operations, board composition, management, strategy and future plans" of Six Flags.

Weitz earlier this month filed similar paperwork, giving him the option to talk with Snyder, Six Flags management or other third parties.

Six Flags stock has risen since Snyder released his takeover bid. It closed yesterday at $7.09, more than the $6.50 Snyder has offered to pay for Six Flags shares if his bid to join the board is approved.