NEW YORK (Reuters) - The surging share price for automaker Tesla Inc TSLA.O this month has slammed short-sellers of the stock with more than $2 billion in losses on paper so far in June, according to financial analytics firm S3 Partners.

FILE PHOTO: Signage is displayed outside of Tesla Motors before the Tesla Energy Powerwall Home Battery event in Hawthorne, California April 30, 2015. REUTERS/Patrick T. Fallon

Tesla shares are up 20.5 percent in June, on pace for their biggest monthly gain month since August 2014, boosted by optimism the company can meet production targets for its Model 3 sedans.

The sharp gains have caught short-sellers in a tough spot, putting their mark-to-market losses for June to $2.09 billion, S3 data showed.

Short-sellers aim to profit by selling borrowed shares with the hope of buying them back later at a lower price.

“In all of 2017, they (short-sellers) were down $3.4 billion. To lose $2 billion in a month, stands out as one of the biggest losses for a stock that I have seen,” said Ihor Dusaniwsky, head of research at S3 in New York.

With Tesla shares up about 2 percent in late afternoon trading on Tuesday, shorts were down $278 million in mark-to-market losses, in addition to $549 million in losses on Monday, said Dusaniwsky. That makes it the worst performing stock for short sellers this year, he said.

On Tuesday, Tesla shares rose as much as 6.9 percent to a 3-1/2 month high of $354.97, before paring gains on news that the electric carmaker would cut 9 percent of its staff, or several thousand jobs, across the company as it seeks to reduce costs.

Tesla short interest stands at $12.6 billion, with 37.9 million or nearly 30 percent of the share float, sold short, according to S3 data.

Shares of heavily shorted companies can at times get pushed higher as traders rush to buy stock to cover their short bets, triggering what is known as a ‘short squeeze.’ That has not happened so far for Tesla, according to S3 data.

There has only been a small drop in the number of shares sold short in June.

“With almost 80 million shares traded in June this slight short covering did not move Tesla’s stock price,” said Dusaniwsky.

“This is the biggest cry wolf on Wall Street - everyone says short squeeze, and it never is. They will be right one day, but not today,” said Dusaniwsky.