During Monday trading, shares of his electric car company Tesla (TSLA) surged over 6% midday to an all-time high, giving the company a market capitalization of $48 billion — and even beating traditional automobile maker Ford’s near $45 billion valuation. That came after Tesla announced better than expected deliveries for the first quarter of 2017.

Those gains, however, caused painful losses to the investors shorting, or betting against, 26.5% of Tesla’s tradable shares as of mid-March. Those short-sellers lost some $488 million as the stock rose on Monday alone, according to S3 Blacklight. That increased their total losses from shorting Tesla in 2017 to $2.74 billion.

Musk didn’t pass up a chance to make a cheeky jab at those doubters. In a Monday tweet, he wrote: “Stormy weather in Shortville…”

Stormy weather in Shortville …

— Elon Musk (@elonmusk) April 3, 2017

Maybe Musk was relishing the fact that his warning to short sellers almost exactly a year ago, also via Twitter, proved prescient. Since Musk said last April that shorting his stock is “probably unwise,” shares have risen 19%.

Tesla’s short-sellers are an enormous contingent, especially considering that Snap (SNAP), for example—the so-far profitless company behind Snapchat, with losses greater than both Tesla and Twitter combined—has reported short interest totaling just about 8.6% of its tradable shares.

Among the most notable of those short-sellers is Kynikos Associates hedge fund manager Jim Chanos. The investor famed for shorting Enron before its collapse has compared the electric car company to troubled stock Valeant Pharmaceuticals (VRX), and characterized Tesla’s acquisition of SolarCity as a “bailout.” After all, both have been considered cash burning machines with no profit to show. But most investors haven’t seen much of Enron in Tesla. Since Chanos unveiled his short position in the company in September, Tesla’s stock has risen 49%. Similarly, since the short-seller who helped take down Valeant, Andrew Left, announced his position against Tesla just over a year ago, shares of the company are up 56%.

If they did choose to give up and “cover,” or close out their short positions, Left and Chanos wouldn’t be the first to admit defeat against Tesla. Kase Capital hedge fund manager Whitney Tilson already paved the way in 2014. Back then, shares rose from about $34 in 2012 to about $205—making it a “traumatic experience” for Tilson, he said recently.

And coincidentally or not, Musk has been right about his stock on more than one occasion. Not only has the stock risen since Musk called shorting Tesla “unwise,” the stock also slid after Musk implied the stock was overvalued. Back then, he told CNBC that “people sometimes get carried away with our stock. … Our stock price is kind of high right now.”

But even if Tesla’s bears have been wrong about the stock over the last year, they aren’t wrong to have doubts about the company. After all, investors have put enormous hope on Tesla’s mass market car, the Model 3—a vehicle that has yet to be fully unveiled by a company with a history of production woes.

This story has been modified to include new data on Tesla short-sellers’ financial losses.