At least two groups of American hedge funds have bought large chunks of Tim Hortons shares recently, a sign the activist investors want to push the company to make major changes to its business, or possibly give up some control over the company.

In a regulatory filing Tuesday, New York-based Scout Capital Management LLC revealed it recently bought 6.1 million shares in Tim Hortons, bringing its total stake to 8.4 million, good enough to own 5.5 per cent of the company.

"[We] have engaged and expect to continue to engage in discussions with senior management of the Issuer with respect to [Tim Hortons'] capital structure, capital expenditures, timing and magnitude of share repurchases, management compensation metrics, and technology investments, among other matters," Scout said in a regulatory filing known as a 13-D, filed with the SEC."

Scout's purchase is large enough to make the fund the second-biggest individual owner of Tim Hortons shares, just behind a conglomerate called FMR which includes mutual fund firm Fidelity Investments.

Last month, another activist hedge fund known as Highfields Capital Management upped its stake in the coffee and doughnuts chain to 6.4 million shares, or almost four per cent of the company. Highfields is now the eighth-largest owner of Tims stock.

Highfields reportedly wants to boost returns by getting Tim Hortons to buy back some of its own shares, scale back on ambitious U.S. expansion plans and possibly spin its real estate assets off into a trust.

Tim Hortons did not immediately reply to a request for comment on this story by CBC News.

The move to shake up one of Canada's most iconic businesses comes on the heels of two similar fights at other companies. Canadian Pacific Railway was the target of a lengthy proxy battle by Bill Ackman's fund Pershing Square, which eventually succeeded in having the CEO replaced.

And last year, fertilizer chain Agrium was able to rebuff an aggressive push by Jana Partners LLC, which wanted to break up the company and sell it off in parts.