New York CNN Business  — 

This has got to make Tesla CEO Elon Musk happy: In the last seven months, short positions on Tesla shares have lost $8.4 billion, according to S3 Partners, a financial analytics firm.

That’s more than the short losses on any other company. The second biggest loss for short sellers came at Apple shares, where they lost just under $6 billion in the same period.

But Apple (AAPL) is a much larger company and the short positions on it are much, much smaller than those on Tesla (TSLA). Short selling accounts for about 21% of Tesla (TSLA) stock sales currently, compared to about 1% of Apple (AAPL) shares.

Short sellers bet that the price of a stock is likely to go down. If it rises before they can cash out their position, they must buy shares at the higher price to cover their bet. Their losses are theoretically unlimited, and often astronomical.

Tesla shares have been on a run lately, inflicting pain on the the short sellers’ positions.

Since hitting a 52-week low of $176.99 on June 3, Tesla stock is up about 150%, fueled by sales and profit numbers that surprised both the skeptics and Wall Street. On Friday its shares gained another 3% to close at $442.98 after reporting record fourth quarter sales that met its earlier guidance.

In just in the first two trading days of 2020, the shorts have lost more than $700 million, according to S3.

Some short sellers have retreated from their positions on Tesla in recent months. About 36% of its shares were being sold short in May, but many Tesla shorts continue to hold on, convinced the market will turn against the upstart electric automaker, especially as established automakers flood the market with their own electric vehicles.

“Some of short-term shorts have been taken out. But many of the longer-term shorts, they’re sticking with it no matter what the price moves are,” said Ihor Dusaniwsky, head of predictive analytics at S3.

Musk has been particularly vocal about his disdain for shorts.

He insists they are deliberately trying to hurt the company by driving down shares, cutting off the company’s access to capital markets. In 2018 Musk even floated the idea of taking Tesla private – not having to deal with shorts was a major motivation for that plan. At the time, he said their “negative propaganda” was another reason to get out of the public market, and that being a public company creates “perverse incentives for people to try to harm what we’re all trying to achieve.”

In November, Musk tweeted shots at one of his harshest critics, Greenlight Capital’s David Einhorn, offering to send him a “small gift of short shorts to help you through this difficult time.”

Despite his public feuds with short sellers, a Tesla spokesperson said the company did not immediately have a comment on the analysis showing short sellers’ losses on Tesla shares.