Tesla shares fell sharply, and that move translated into major paper gains for investors betting against the company. The report said short sellers were ahead by about $9 billion as the stock declined, with roughly $4.3 billion of that amount coming in a single trading session.

Short sellers make money when a stock drops because they are positioned for the share price to fall. In Tesla’s case, the slide in TSLA created a large mark-to-market windfall for bearish traders, underscoring how quickly sentiment around a heavily watched stock can shift.

Tesla remains one of the market’s most closely followed companies because of its size, brand recognition, and role in the electric vehicle and energy businesses. That high profile often leads to unusually large moves in both directions, which can produce outsized gains or losses for traders on either side of the market.

The latest decline highlights how volatile Tesla stock can be. While the reported gains for short sellers are still on paper unless positions are closed, the move shows the scale of the recent selloff and the pressure it put on the company’s share price.