Another day has passed since Tesla chief executive officer Elon Musk nonchalantly claimed on Twitter that he had secured funding to take the firm private, and still no evidence has emerged to support his claim.

Shares of the electric-car manufacturer erased gains prompted by his surprise tweet, falling as much as 6% on Thursday.

The losses came amid news that the US Securities and Exchange Commission was “intensifying” a probe into Musk’s statement, as Bloomberg reported. The tweet itself, which sent Tesla shares soaring as much as nearly 11%, is not likely to be considered manipulation, but should his statement prove false, it would constitute fraud.

Reports indicate the probe is in an initial review stage and regulators have yet to launch a formal investigation.

As to the question of whether Musk has indeed secured the funding, there is plenty of skepticism among the Tesla short-sellers to go around.

“Clearly we all believe there’s an extremely low probability he can get that deal done,” Tesla bear Mark Spiegel of Stanphyl Capital said, according to The Financial Times. “He can’t do it with debt, the financials are too horrible. So it’d have to be equity, and there’s not enough stupid money to buy this company at an $80 billion valuation.”

The increasingly public feud between Musk and short-sellers of Tesla stock provided the motivation for Musk to go public. Now the suspense is building to see who will provide the funding.