Leap Wireless International Inc., the flat rate cellphone carrier doing business as Cricket, said a special shareholders meeting to vote on its sale to AT&T Inc. is set for Oct. 24 in Denver.

Leap struck the deal with AT&T in July to sell the business, spun off from Qualcomm in 1998, for $15 per share of common stock or $1.2 billion. Including Leap’s net debt of about $2.8 billion, the value of the transaction is nearly $4 billion.

AT&T’s offer price was an 88 percent premium on the Leap share price before the agreement. Since that time, shares rocketed to above $17 but have been trading a little above $15.50 in recent weeks, giving the company a market capitalization of $1.24 billion.

In the most recent filing, Leap Wireless said it faces a termination fee ranging from $46 million to $71 million if the deal falls through.

A Leap spokeswoman gave no reason for the site choice for the special meeting.

Nearly 30 percent of the company’s outstanding shares are in support of the sale, the company said.

— Mike Allen