McDonald's Corp. (MCD) Friday said quarterly net profit more than tripled as its U.S. business improved further and signaled it might pursue a spinoff or other options for its Chipotle Mexican-style restaurant chain.

Excluding one-time items, the results fell a penny short of Wall Street analysts' average estimate, and McDonald's stock fell about 2 percent.

Net income for McDonald's fourth quarter rose to $397.9 million, or 31 cents per share, from $125.7 million, or 10 cents per share, a year ago.

Excluding a one-time gain for the sale of a real estate partnership and charges for asset impairment and a change in the way it accounts for leases, McDonald's earned 45 cents per share, a penny below Wall Street analysts' average estimate of 46 cents per share, according to Reuters Estimates.

Chipotle, one of several small chains McDonald's operates, has capitalized on the demand for quick, fresh food known as fast casual. But despite the chain's success, McDonald's in recent years has downplayed its so-called partner brands to focus on improvements to its mainstay hamburger chain.

In Friday's statement Chief Executive Jim Skinner (search), who took over from the late Charlie Bell (search) in November, said raising additional funds for the 400-store chain would allow McDonald's to put more resources into its namesake restaurants.

"We believe Chipotle's value and potential might be maximized through alternative strategies that could include raising additional equity capital in the public or private markets," Skinner said.

Revenue rose 10 percent to $5.01 billion, while sales at McDonald's restaurants open at least 13 months, a key retail measure known as same-store sales, rose 5.1 percent.

McDonald's flagship U.S. business was particularly strong due to the company's two-year effort to boost sales with new menu items such as its Chicken Selects (search) fried chicken strips, later hours, and revamped advertising.

But sales at McDonald's European unit, which have suffered due to economic weakness in countries like Germany, are improving, the company said.

"We are building momentum and making progress revitalizing this important business segment," Skinner said.

McDonald's shares were down 68 cents, or 2.1 percent, at $31.44 Friday on the New York Stock Exchange (search).