GameStop Corp. has made an audacious $56 billion bid for eBay Inc., deploying a financing tactic straight from the corporate raider playbook of the 1980s. The meme-stock retailer is using a "highly confident" letter from TD Bank to prove it has the means to carry out the deal — if not the cash in hand.

The "highly confident" letter, a tool made famous by Drexel Burnham Lambert during the junk bond era, signals that a lender believes financing can be arranged without actually guaranteeing the funds. This approach allows target companies to assess the credibility of a bid without the buyer having fully committed capital.

The strategy marks a bold escalation in GameStop's attempt to transform itself from a struggling video game retailer into a broader e-commerce player. Whether the market takes the bid seriously — or views it as another episode of the company's meme-stock theatrics — will depend on whether eBay engages in negotiations.