The crux of Ryan Cohen’s $55 billion bid for eBay is a letter, signed by a bank and meant to convince the market and eBay’s board that he can pull off an unprecedented takeover of a company four times its size. So where is it?

Pioneered by Carl Icahn and the debt wizards at Drexel Lambert in the 1980s, highly confident letters are formal, nonbinding letters that are usually used by investment banks or lenders to broadcast a belief they can secure the financing they need for a transaction. The letters, promises to the world that the bidder is good for the money, are particularly helpful for situations just like this, where one party (eBay) isn’t interested in doing a deal with the other (GameStop).

But Cohen’s bid is a little different than hostile takeovers we’ve seen in recent years. Cohen’s financiers at TD Bank don’t have a lot of experience backing corporate takeovers. The letter itself is closely held, and even some of Cohen’s own advisers don’t have access to it, according to people familiar with the situation. (eBay has seen the letter and believes that it does not represent a workable financing package, according to people close to the company.)

Representatives for both GameStop and eBay declined to comment.

Within that letter, according to people who have viewed it, are a series of assumptions that caveat TD’s willingness or ability to raise the $20 billion in capital for Cohen, including an assumption that a combined eBay-GameStop would be able to attain an investment-grade rating if the deal goes through.

Today, eBay is rated on the cusp of investment-grade. That’s before adding $20 billion in debt to the company, which Cohen’s bid would do. Moody’s has already weighed in on what the combination would do to eBay, saying Tuesday that a deal “credit negative to eBay because of the substantial increase in financial leverage.”

This adds to concerns over whether Cohen is a serious acquirer, especially one trying to swallow a company four times its size. He seems unconcerned with the potential dilutive effect of his bid — 50% cash, 50% stock, as he told CNBC — nor with giving Wall Street more information about his efforts.

But judging by the market’s reaction to his bid, investors have already figured out that he’s not.