With Lyft (LYFT) - Get Lyft Inc Class A Report shares wavering in their first full week of trading, short sellers are on the move. 

Short interest in Lyft Inc. topped 13 million shares as of Apr. 4, according to S3 Partners, which tracks short interest in publicly traded companies. The 13.38 million shares shorted are equivalent to more than 41% of its overall float, and $937 million in total short interest. As a percentage of total float, Lyft had the highest short interest among U.S. stocks with short interest over $50 million. 

A pair of downbeat analyst notes on Lyft's stock led to a selloff earlier this week, though shares bounced back by Thursday to open at $70.48. Lyft shares rose 2.86% on Thursday, closing exactly at their IPO price of $72 per share.

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Still, short interest in Lyft's stock edged upward on Thursday, according to S3's data, from 12.4 million shares shorted on Wednesday. And Lyft's stock is likely to draw significant short interest for weeks to come, according to Igor Dusaniwsky, managing director at S3 Partners.

"As we have seen in most IPO's, shares shorted usually takes several weeks to plateau as short sellers leg into their positions over time, so we should see over $1 billion in LYFT short interest very soon and if the short selling trend continues, closer to $1.2 billion within a few weeks," wrote Dusaniwsky.

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