The U.S. Internal Revenue Service is auditing Uber Technologies' taxes for 2013 and 2014 and the ride-hailing company expects unrecognized tax benefits to be reduced within the next year by at least $141 million.
In its full quarterly report on Tuesday, Uber said various state and foreign tax authorities were also looking into its taxes and that it was currently unable to put a definite timeline or estimate on the overall adjustments that might result.
The $141 million amount related only to its transfer pricing positions, which refers to the common multinational practice of charging for services between wholly-owned businesses in different countries or jurisdictions to reduce the tax it pays.
Industry experts characterize transfer pricing as a relatively risky strategy, which typically is among multinationals' top tax concerns and has been used by authorities in the past to go after Apple Inc and Amazon.
"Although the timing of the resolution and/or closure of the audits is highly uncertain, it is reasonably possible that the balance of gross unrecognized tax benefits could significantly change in the next 12 months," the company said.
Uber did not respond to a request for additional information.
The announcement came on a day when at least 11 of the brokerages whose underwriting arms backed Uber's Wall Street debut last month weighed in with "buy" recommendations on the company's shares as a statutory embargo lifted.
Also helped by a recovery for Wall Street from a technology sector sell-off on Monday, Uber shares gained almost 3 percent in trading before the bell.
Uber's shares have struggled since its launch on May 10. Tuesday's pre-market moves took them above their closing price on the first day of trading, but they remain below the $45 at which the original offer was priced by its underwriters.
Still, the shares have outperformed rival Lyft, which have fallen by a third in value since its own debt in March, and analysts from Deutsche Bank said the stock remained the best internet IPO for investors since Facebook's launch in 2012.
In its first quarterly report as a public company last week, Uber reported a $1 billion loss as it spent heavily to build up its food delivery and freight businesses.
But many of the analysts covering the stock on Tuesday said they believed it had the scale and time to develop into another powerful U.S. global tech player.
"Uber should trade at a premium to LYFT given Uber's larger global scale and reach, cross product growth opportunity and larger ability for long-term leverage," said analysts at Morgan Stanley.
"It is still in the early innings in its core and emerging opportunities."