* Hedge fund called for break up of Credit Suisse last year
* Credit Suisse says fund no longer a registered shareholder
* RBR says it has not reduced its stake (Recasts with comment from RBR)
By Brenna Hughes Neghaiwi
ZURICH, April 18 (Reuters) - Activist investor RBR Capital Advisors, which last year called for Credit Suisse to be broken up, does not hold any registered shares in the bank, both parties said on Wednesday.
However, a spokesman for RBR said the hedge fund founded by investor Rudolf Bohli had not reduced its stake in Switzerland's second-biggest bank - only that the shares were not registered.
"Rudolf Bohli no longer owns any Credit Suisse shares entered in the share register," a Credit Suisse spokesman said.
He added it was possible RBR held a so-called economic interest in shares via an account with a prime broker, but that this would not give RBR any voting rights.
The RBR spokesman declined to say how its shares were held.
RBR rose to prominence through high-profile, but ultimately unsuccessful, campaigns against asset manager GAM and airline caterer Gategroup.
Last year it proposed a break-up of Credit Suisse, saying it had taken a 0.2 percent stake in October.
But the bank flagged a reduction in RBR's stake just a month and a half later, which the hedge fund denied.
Credit Suisse shares have risen 2.8 percent since Bohli announced his initial proposals on Oct. 17. They were flat at 1405 GMT, in line with the Stoxx European bank index.
Prime brokers, usually large banks, make money from hedge funds by providing services such as stock lending, financing and trade execution.
Credit Suisse holds it annual general meeting on April 27, at which RBR will not be able to make proposals or vote on agenda items.
Major shareholder advisory groups are backing the bank's pay proposals after it overhauled a compensation policy that provoked criticism last year.
In January, RBR announced the closure of one of its funds and said it would be placing greater emphasis on shareholder activism. It also shifted its focus on Credit Suisse by calling for it to revamp its IT platform and cut jobs. (Reporting by Brenna Hughes Neghaiwi; Edited by Michael Shields and Mark Potter)