Uber confirmed that the Internal Revenue Service is taking a look at its 2013 and 2014 tax returns.
The company, which lets you hail a ride through an app on your phone, released the information Tuesday in a regulatory filing, adding that "various state and foreign tax authorities" are also looking into its taxes.
Uber said it isn't sure how much any adjustments will amount to or when they'll be made, but the company said it's reserved "adequate amounts" to cover any costs.
Uber declined to comment beyond what's in the filing.
The filing comes a week after the company announced its first-quarter earnings as a public company, which included a $1 billion loss but a slight rise in revenue.
The ride-hailing service had a bumpy debut on Wall Street in May and has struggled since then.