WeWork has filed a lawsuit against SoftBank Group Corp., its biggest shareholder, after the Japanese investor scrapped a US$3 billion agreement to buy stock from former Chief Executive Officer Adam Neumann and other shareholders.

SoftBank breached contractual obligations and fiduciary duty by failing to complete the deal, WeWork said in a statement on Tuesday.

“Instead of abiding by its contractual obligations, SoftBank, under increasing pressure from activist investors, has engaged in a purposeful campaign to avoid completion of the tender offer,” WeWork parent We Co. said in the statement.

SoftBank had agreed to buy the shares from Neumann, Benchmark Capital and others as part of a bailout package last year, but notified stockholders in mid-March that conditions for the deal hadn’t been met. On Thursday, after the deal’s deadline passed, SoftBank confirmed it would end the offer, citing five conditions that were not satisfied by the closing date.

The lawsuit was filed in the Delaware Court of Chancery.