Tinder's parent companies have been accused of undervaluing the dating app, cheating executives out of billions of dollars worth of stock options.

A group of 10 current and former top staff - including the firm's co-founders and former boss - made the claim in a lawsuit filed in New York.

They are seeking at least $2bn (1.57bn) in damages from the parent firms IAC and subsidiary, Match Group.

IAC and Match said they would fight the suit, calling the claims "meritless".

The two firms said the valuation occurred under a "rigorous, contractually-defined" process.

The plaintiffs "did not like the outcome," they said, adding that Match has paid out more than $1bn in equity compensation to Tinder's co-founders and employees.

"We look forward to defending our position in court."

Tinder launched in 2012 on the back of the explosion in smartphone use. Just two years later it was registering more than a billion "swipes" a day.

The app is one of several brands that falls under the Match Group umbrella.

Media giant IAC owns the majority of Match, which it spun out as an independent, publicly-traded company in 2015.

The lawsuit concerns share options granted to certain Tinder staff in 2014, which gave them the right to buy Tinder shares at pre-set times, starting in 2017.

'False picture'
The employees, who include three co-founders and several current executives, say IAC/Match created a "false picture" of Tinder's financial condition and prospects in order to reduce the value of stock options awarded.

For example, during the valuation, IAC/Match estimated that Tinder would bring in $454m in revenue in 2018, according to the filing.

This month, Match told investors Tinder's 2018 revenue would be about $800m.

"When it came time to pay the Tinder employees what they rightfully earned, the defendants lied, bullied, and violated their contractual duties, stealing billions of dollars," the attorney for the plaintiffs, Orin Snyder of Gibson, Dunn & Crutcher, said in a statement.

The employees also accuse IAC/Match of overlooking sexual misconduct by a Match Group executive.