UBS AG, trying to reprise its success in limiting fines in a probe of interest-rate rigging, is seeking immunity in the U.S. and European Union as part of the global investigation of currency markets, Bloomberg News reported yesterday. UBS saved itself billions of euros in fines in December by disclosing to the EU its role in manipulating the London Interbank offered rate. Now, the bank aims to be the first to report its own conduct in currency markets to European and American regulators, said the people, who requested anonymity because the matter isn’t public. The Zurich-based bank is making its bid for leniency as at least a dozen regulators probe allegations that traders colluded to rig benchmarks in the $5.3 trillion-a-day currency market.