State Street Corp said on Thursday it is not looking to buy Credit Suisse, in its first outright dismissal of a Wednesday morning report that it was seeking a deal.

U.S.-listed shares in Credit Suisse were last trading down 3.7% after falling as much as 8.4% following reports of the U.S. company's denial. State Street shares were last up 0.2% after spiking as much as 3% higher.

Credit Suisse shares had spiked higher on Wednesday afternoon and State Street shares lost ground, with traders citing a report by Swiss financial news blog Inside Paradeplatz that U.S-based State Street was planning a takeover bid for the troubled lender, though many in the industry expressed doubts about the claim.

"State Street is not pursuing an acquisition of, or any other business combination with, Credit Suisse," State Street said in an emailed statement. "There is no basis to the continuing market rumors."

"We feel a response to these reports is now warranted in this instance," State Street said, as it in the process of buying Brown Brothers Harriman Investor Services, a deal that was announced last year.

Credit Suisse Chief Executive Thomas Gottstein earlier Thursday called queries over a potential takeover offer from the U.S. bank "really stupid," shutting down questions.

"We never comment on rumours. And my father once gave me advice: For really stupid questions, you better don't comment at all," Gottstein said, flagging a related question at the Goldman Sachs European Financials Conference.

"So I think I will listen to my father's advice on this one."

Switzerland's second-largest lender has described 2022 as a "transition" year in which it is trying to turn the page on costly scandals that prompted a near total reshuffle of top management and a restructuring seeking to curtail risk-taking, particularly in its investment bank.

Its shares have lost nearly half their value since two of the biggest shocks - the collapse of $10 billion in supply-chain finance funds linked to Greensill Capital and a more than $5 billion loss on the unwinding of trades by investment firm Archegos - hit the bank in March 2021.

Those blows prompted questions over whether the flagship Swiss lender could be challenged by investors demanding its break-up, or that its shrinking stock-market value made it a target for a foreign hostile takeover.

Reuters reported in April 2021 that State Street was among investors expressing interest in Credit Suisse's asset management arm.

Gottstein said on Thursday that no joint venture or strategic option was on the table for the business, and said asset management remained a key division for Credit Suisse.

The bank warned on Wednesday of a likely second-quarter loss and said it now aims to bring cost savings forward.

Gottstein said that alongside accelerating cost initiatives, the bank would slow down some of its investments.

"In some areas, we are waiting a little bit with some of the growth investments," he said. "In China, we had a plan to ramp up relationship managers by about one-third in each year (from 2022-2024). That RM growth, we're going to slow down a little bit."

The bank, however, remained committed to its China plans, he said, disputing a report by Bloomberg earlier on Thursday.

"I want to be very clear: Our overall China roll-out is fully on track. There was some news that we are delaying our licence application for the (licensed bank), which is not true. We are fully on track on that. We also want to get to 100% on our China securities joint venture," he said.