FORT WORTH—RadioShack Corp.'s long-awaited Chapter 11 bankruptcy filing came late Thursday afternoon, with the beleaguered electronics retailer saying it had agreed to sell between 1,500 and 2,400 of its 4,000 company-owned stores to hedge fund Standard General LP, its largest shareholder. Up to 1,750 of those sites would be co-branded with wireless operator Sprint, which would establish a store-within-a-store at these locations. The remaining company-owned stores—between 1,500 and 2,500, depending on the size of the sale to Standard General—will be closed.

Sprint said Thursday that it had reached an agreement with General Wireless, the Standard General subsidiary formed to buy a portion of Radio Shack's owned stores, to occupy about one-third of the space at each retail location. Sprint employees will sell mobile devices and plans on all Sprint brands in these spaces, including Boost and Virgin Mobile. Sprint will be the primary brand on storefronts and in marketing materials for these locations, which would more than double the wireless company's current store count.

“These steps are the culmination of a thorough process intended to drive maximum value for our stakeholders,” RadioShack CEO Joe Magnacca said Thursday. As part of this process, other parties will have an opportunity to submit offers for RadioShack's assets in a court-approved process. Amazon.com, which has begun to establish a brick-and-mortar presence, reportedly was interested in acquiring some of the locations.

In its Chapter 11 petition, filed Thursday at US Bankruptcy Court in Delaware, RadioShack listed assets and liabilities of more than $1 billion. It also listed between 50,001 and 100,000 creditors.

The company has filed a motion with the bankruptcy court to proceed with closure of its remaining company-owned stores under an agreement with Hilco Merchant Resources. The roster of underperforming stores slated to go dark has not yet been made public; the company's franchise-operated RadioShack locations in 25 countries are not part of the bankruptcy filing.

For the 94-year-old electronics chain, the bankruptcy filing marked the culmination of a long decline. It posted losses for each of the past 11 quarters, and first broached the possibility of a Chapter 11 filing last September, citing “a prolonged downturn in our business.” It was delisted by the New York Stock Exchange earlier this week, by which time its stock had plummeted to 24 cents per share.

RadioShack said Thursday it had secured a commitment for approximately $285 million in debtor-in-possession financing from its current ABL lender group, led by DW Partners LP.  The DIP is intended to provide it with liquidity during the sale process.