Shares of Lyft (LYFT) - Get Reportopened at just above $87 a share, 21% above its offering price of $72, as the ride-hailing rival to Uber debuted on the Nasdaq on Friday morning. 

As for many fast-growing tech companies, there was strong demand for Lyft's stock. Lyft's revenues more than doubled in 2018 to $2.2 billion, but the company also lost $911 million as it spent heavily to grow and compete with Uber.  

Experts say investors should keep an eye on the longer-term growth prospects of the company, as it could take a while for the stock to find its true price. 

"Lyft is popping the Dom Perignon today, but how the stock trades over the coming months and especially once Uber comes out and goes public will be the real test in our opinion," said Wedbush Securities analyst Dan Ives. He added that "this is a lightning start for Lyft's stock as investors are salivating [about] owning a piece" of what is expected to be a massive ride-sharing market over the next few years. 

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"An investor should really maintain focus on time horizon," said Alejandro Ortiz, Principal Analyst at Sharespost, a provider of both research and liquidity to investors in private companies and unicorns. "These are really long plays if you think about the growth prospects of these companies, and that's really the focus."

One observer thinks Lyft's valuation is out of control, however. 

"The valuation at this level makes no sense," said Eric Schiffer, CEO of the Patriarch Organization, a venture capital and private equity firm that invests in digital media companies. "Lyft is an IPO disaster waiting to hype [already] influenced investors," Schiffer said, noting that Lyft makes $2 for every $3 it spends. 

Lyft has certainly been unprofitable during its existence, but there's an argument for a path to profitability. "These [newly public growth and tech firms] are valuable not because they're making profit," said Ortiz. "Their ridiculous growth rates are why they're valuable." 

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