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Traders going long on shares of Tesla had the last laugh in 2019.

At the end of the year, short-sellers betting against Tesla lost $2.9 billion on a mark-to-market basis, according to a Friday tweet from Ihor Dusaniwsky, managing director of predictive analytics at S3 Partners, a financial-analytics provider.

The second half of the year was particularly painful for short-sellers as the stock rallied nearly 70% from its 2019 low in June through December. Short-sellers lost nearly $8 billion mark-to-market as shares surged over the seven-month period, according to S3 data.

The stock price gains even forced some short-sellers to abandon, or "cover," their positions against Tesla.

"What was a seven month long 'hug' is turning into a full-blown 'squeeze,'" Dusaniwsky wrote in a December 2019 note.

The pain is continuing into the new year. On Friday, Tesla shares surged as much as 5% to a fresh high after the company reported record fourth quarter and full-year 2019 delivery numbers.

Tesla short-sellers are down $330 million mark-to-market in the first few trading days of January, according to S3 data. While it's too early to see if shorts experience another squeeze from Friday's gains, one could restart if the stock continues to rally, Dusaniwsky said in another tweet Friday.

Tesla gained 26% in 2019.

Markets Insider

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