Sprint Corp. (S) has ended talks to acquire T-Mobile US Inc. (TMUS), a person with knowledge of the matter said, after talks reached an impasse amid disagreements over financing and a drop-dead date for a merger.

The third-largest U.S. wireless company plans to name a new chief executive as soon as tomorrow to replace Dan Hesse, said the person, who asked not to be identified because the information is private.

T-Mobile sent Sprint a list of requirements, including the financing structure and the date after which one side can walk away if a transaction hasn't been completed, said the people, who asked not to be identified discussing private information. T-Mobile is controlled by Deutsche Telekom AG. (DTE)

T-Mobile, which was approached about a stake purchase by Iliad SA last week, was willing to move forward on a deal with Sprint if the third-largest U.S. wireless company agreed to all the sticking points, the people said. Both companies viewed regulatory approval for a deal as a long shot, two people said, given the current Obama administration's stated goal of having four competitive wireless companies in the U.S.

Scott Sloat, a spokesman for Sprint, declined to comment. Anne Marshall, a spokeswoman for T-Mobile, didn't immediately respond to a request for comment.

T-Mobile and Sprint shares slid in late trading. The Wall Street Journal reported earlier that Sprint dropped its plans to buy T-Mobile.

To contact the reporter on this story: Alex Sherman in New York at [email protected]

To contact the editors responsible for this story: Mohammed Hadi at [email protected] Elizabeth Wollman