According to a New York University professor, Musk would have to borrow money against his shares in order to buy Twitter.
The CEO of the two companies offered to purchase the social media platform for $43 billion on Wednesday.
Scott Galloway, who is a professor of marketing at NYU's Stern School of Business, said that despite an estimated fortune of $259 billion, Musk has no viable route to financing the deal without putting the stock at risk.
He co-hosted with tech journalist Kara Swisher on the New York magazine show.
According to the billionaires index, Musk has over $2 billion in cash.
The first option is with debt, and he can't because his company has no earnings. No firm is going to lend him more than a billion or a few billion dollars, so he has to come up with 40 billion in equity.
He could go to his friends and ask them to give him money, but Musk's buddies were more interested in money than free speech, according to Galloway.
He said that the only viable source of financing was for him to borrow against his shares in the company.
Musk would have to borrow up to $300 billion in equity value, and no single bank is going to be the bank.
Musk would have to go to several banks. I think it would still be the most valuable car company in the world, then all of a sudden, Musk would get margin calls and be forced to sell his stock.
If this deal were to go through, he would raise money against the shares of the company. The stock would tank.
Galloway did not respond to the request for comment made outside of normal working hours.
Musk said earlier this month that he had become the company's largest individual shareholder. The company is an asset management company.
Musk turned down the offer of a board seat. Musk would not be able to gobbling up the whole company if he joined the board.
If Musk buys the company, it will result in job losses as employees look for other tech companies.