AMC short-sellers just lost $2.8 billion in a single day - and they're now down $4.5 billion in 8 days amid a 500% surge for the stock

• AMC short-sellers lost $2.8 billion on Wednesday alone as shares skyrocketed as much as 127%
• They're now down $4.5 billion in just eight days, since AMC shares began a torrid surge that capped out at more than 500% on Wednesday afternoon.
• AMC shares have benefited from renewed interest from Reddit day traders seeking to squeeze out short positions.

Short-sellers betting against AMC stock lost $2.8 billion on Wednesday alone as shares skyrocketed as much as 127%. They're now down $4.5 billion in just eight days, since AMC shares began a torrid surge that capped out at more than 500% on Wednesday afternoon, according to data from analytics firm Ortex.

AMC slid 3% to $60.47 on Thursday as of 9 a.m. in New York.

Short-sellers felt the pain in other meme stocks as well as Reddit day traders banded together to execute squeezes of bearish positions. Shares in home retailer Bed Bath & Beyond rallied 62%, adding up to $681 million in losses, while retail chain GameStop's stock rose 13%, delivering $414 million in losses, according to Ortex.

It's activity reminiscent of the GameStop mania that dominated market activity in late January and early February, and the market's most heavily shorted stocks - including AMC - are once again in focus. Mark-to-market losses from the 10 most-shorted US stocks totaled $4.5 billion just on Wednesday, Ortex data shows.

Yet despite the deep losses, short-sellers appear relatively unperturbed. The percentage of AMC's free float held short had actually increased to 18% on Wednesday, up from 15.5% a week prior, according to Ortex. Further, data from Bloomberg showed that shorts only slightly pared their positions on Wednesday as AMC's wild spike was transpiring.

"If you, as an investor, believe the share price will go back to where it was at the beginning of the year, shorting the stock [now] could bring huge profits," Ortext cofounder Peter Hillerberg told Insider.

He continued: "However, so far, the short bets haven't paid off, as the upward momentum in AMC has been going for a few days now and seems to only be increasing."

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