Starbucks Says It Is Not Buying Chipotle. The Denial Sends Chipotle Shares Tumbling.

Starbucks and Chipotle are among the largest restaurant chains in the U.S., with both companies focused on improving customer traffic and sales. (Credit: IBT US)

Starbucks has ruled out acquiring Chipotle Mexican Grill, putting an end to days of takeover speculation that sent shares of the Mexican fast-casual chain higher last week and raised questions about a potential multibillion-dollar restaurant industry deal.

"Starbucks is not buying Chipotle," a company spokesperson told CNBC Monday in a direct denial of reports that the coffee giant was considering a takeover of the burrito chain.