A Concord, Mass.-based investment firm that owns shares in Six Flags Inc. said yesterday that it planned to vote in favor of Redskins owner Daniel M. Snyder's bid for control of the theme park company.

Tigris Management LLC, in a news release, said Snyder and his partners, former ESPN executive Mark Shapiro and home builder Dwight C. Schar, have a "successful track record that can unlock the potential value in Six Flags."

"Red Zone should have a chance to fix this mess," Tigris partner Murat Azizoglu said in a telephone interview, referring to the Red Zone LLC partnership that Snyder uses to hold his Six Flags shares.

The impact of Tigris's decision on Snyder's effort was unclear. Azizoglu declined to reveal how many shares he controls -- though it is less than the 5 percent stake that would have required him to disclose his holdings with the Securities and Exchange Commission. The firm was incorporated in Florida in March 2004 by Azizoglu and two Florida residents, public records show.

Six Flags said it could not confirm how many shares Azizoglu owns.

Six Flags executives on Tuesday referred to Snyder's bid as "the most urgent crisis" facing the company. Chairman and chief executive Kieran E. Burke said during a Tuesday conference call with analysts that he and other Six Flags officials have been visiting shareholders to tell them that turning the company over to Snyder and his team would be "a risky bet."

He said the company's 10 percent increase in revenue and 4 percent increase in attendance during the third quarter were evidence that management has been successful at reviving Six Flags, whose revenue and attendance have fallen sharply in recent years.

Six Flags managers said Snyder was trying to gain control of the company without having to buy it and told shareholders they would benefit more from a sale of the company. The Six Flags board, which put the company up for sale in August, said it has received several potential offers and expects to have a final offer to present to shareholders by the end of the year.

To succeed in his bid, Snyder, Six Flags' largest shareholder with an 11.7 percent stake, needs to secure the approval of owners of a majority of shares. Last week, New York investor Simon Glick, who controls about 9.8 percent of Six Flags shares, said he would vote for Snyder's proposal. Other major shareholders include Microsoft Chairman Bill Gates, who owns 11.5 percent, and Omaha fund manager Wallace R. Weitz, who controls 10.6 percent.

Since August, when Snyder revealed his plans, shareholders have been barraged with pleas from both sides and, in recent weeks, some have received personal visits. Snyder and Shapiro have been out meeting with shareholders in an effort to persuade them to oust two managers and one director and to install them and Schar instead.

The Titan roller coaster at the Six Flags Over Texas theme park.

Daniel M. Snyder is Six Flags' biggest shareholder.