Lyft has quickly become one of the most shorted U.S. stocks and pricey to bet on

A surge in demand for short positions in Lyft Inc., the ride-hailing company that went public last week, has made it the most expensive bearish bet in the U.S. equity market.

Tuesday was the first day investors were able to borrow shares to settle short sales, and the interest cost of funding a new short stake rose 100%, according to IHS Markit. That makes Lyft the “most expensive to borrow” U.S. stock with more than $5 million in balances, Markit’s director of securities finance Samuel Pierson said in an emailed statement.

In the overnight settlement reports, 6.61 million shares were reported as on loan, for a market value of $455 million, according to Markit data. Lyft is now down 1.4% from its initial public offering price of $72 and has a market cap of roughly $19.7 billion.

Short investors have, however, seen much worse. Earlier this year, the price for shorting the cannabis company Tilray Inc. shot through the roof, with the borrowing cost soaring as high as 900%. Since then, Tilray shares have fallen 20%, even though the stock is up nearly 275% from its July 2018 IPO level.

While Lyft made its debut amid much fanfare on Friday, the shares quickly lost some steam and have fallen below the IPO price as more cautious voices emerge. On Tuesday, Lyft received its first sell rating from Seaport Global analyst Michael Ward, who said that its current valuation required a “big leap of faith” from investors, and reflected an overly optimistic view of consumer behavior in the U.S.

According to financial analytics firm S3 Partners, short sellers had gone into overdrive over the last three trading days and shorted more than 38% of Lyft’s 32.5-million-share float, making it the 27th largest domestic stock among companies with greater than $50 million worth of short interest.

“We can expect Lyft to be a significant short in the market for a long time, especially with analysts already posting ‘sell’ recommendations less than a week after its IPO,” S3’s Ihor Dusaniwsky wrote in a report.

Activist Wall Street investor Carl Icahn sold his 2.7% stake in the ride-hailing company before the IPO, the Wall Street Journal reported. Icahn had invested $150 million in Lyft starting in 2015 and his stake was worth about $550 million at the IPO price.

Skeptics have warned not only about Lyft’s growth trajectory and valuation but also about overhyped IPOs that quickly fizzle after their debut.

With a string of high-profile IPOs expected to drop this year, including Uber Technologies Inc., Pinterest Inc., Postmates Inc. and Slack Technologies Inc., Lyft’s experience could be a “major gut check” for the technology IPO world, Wedbush analyst Daniel Ives said in a note Tuesday.