Lyft sank 1.8% on Friday, a day after Uber released its S-1 where it reported 2018 revenue of $11.27 billion compared with Lyft's $2.2 billion . Uber said it had a net profit of $997 million in 2018, though it has a loss of $1.85 billion on an adjusted EBITDA basis. Lyft reported a loss of $911 million in its public filing.

The stock started the week priced at $74.45 from it April 5 close, still above its March 28 IPO price of $72. As of Friday's market close, shares traded at $59.90 with a market capitalization of $17.1 billion, marking a new 52-week low.

Shares of Lyft slid 19.55% in the past week as investors finally got their first look inside rival Uber's business . The stock closed in the negative four out of five days this week and dropped about $3 billion in market capitalization.

Still, investors are uncertain about how to compare the two. Besides the different components of their businesses, with Uber investing in its freight and meal delivery services on top of ride hailing, their financials are difficult to stack up.

Wedbush Securities analysts gave Lyft a neutral rating on Friday with a 12-month price target of $80, saying concern it has heard from investors prior to Uber's S-1 were not eased much now that it's public.

"And now that Uber's S-1 was released after the close yesterday we think investors don't yet have a whole lot more clarity on some of the key comparable metrics," the analysts wrote. "Uber does not break out its metrics between the US and international beyond noting that 52% of bookings and 74% of rides come from outside the US. Additionally, Uber defines its rider metrics by combining both rideshare and Uber Eats riders, so generating metrics like billings per ride, revenue per ride and profit per ride are not fully comparable."

The analysts tried to approximate how the two compare, saying Uber's "ridesharing take rate," defined as revenue over gross bookings, was 22% in 2018 compared with Lyft's 26%. But they noted that Uber includes tolls and surcharges in gross bookings, unlike Lyft, and Uber's numbers were global, which suggests a larger spread of its range.

"We believe there could be continued pressure on Lyft shares while investors wait for Uber's roadshow and dig further into the full financial metrics," the Wedbush analysts wrote. "In our opinion, the battle for market share will be balanced going forward. We think there's plenty of work to do and time to go until investors start to feel like they are missing out on the 'next Amazon' although we believe Lyft remains in a strong position to capitalize on this fertile market opportunity."

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Watch: Here's everything you need to know about the 300 page Uber IPO filing