UBS Group AG has been sued by an investor arguing the bank paid less than its rival Credit Suisse Group AG was worth in the government-brokered deal in March, and is demanding compensation.

UBS offered Credit Suisse shareholders just 0.76 Swiss francs ($0.84) for each of their shares, while the stock closed at 1.86 Swiss francs on March 17, the last trading day before the deal was agreed. Offering shareholders less than the then-current stock price goes against all the conventions of takeovers and ignores Credit Suisse’s broader value, wrote lawyer Dimitri Santoro on behalf of his client. 

“In a takeover, the shares normally command a high premium,” the complaint reads. 

The complaint was submitted by Santoro to the Zurich Commercial Court on behalf of an investor whose name was redacted in the copy seen by Bloomberg News. A spokeswoman for the court didn’t immediately reply to say if the complaint has been received or evaluated. 

UBS declined to comment while a spokesperson for Credit Suisse wasn’t immediately available to comment. 

Santoro says his client is seeking compensation of at least 1.06 million francs, based on the per-share discrepancy multiplied by the number of shares he owns. UBS had said it expects to close the deal at the end of May at the earliest, though that timetable is likely being pushed into June. UBS and the Swiss government are haggling over the precise terms of a state guarantee for the deal. 

Were the complaint to make headway it could embolden other shareholders to come forward, adding to the legal headaches for UBS. At least 230 claims representing some 2,500 aggrieved bondholders have been filed in Switzerland since March over the controversial writedown of a class of bonds known as AT1s that was part of the rescue package.

News of the complaint was first reported on Sunday by SonntagsZeitung.  –BLOOMBERG