As ECB policy makers increasingly appear to agree on a June rate cut, Bundesbank President Joachim Nagel tells CNBC that caveats still remain. In the U.S., a Boeing whistleblower testifies in the Senate, blasting his former employer over safety negligence and calling for the grounding of the Dreamliner. UBS is eyeing further lay-offs with cuts likely to fall in banking, markets and wealth management divisions. ABB hikes its full-year guidance after a Q1 beat on a stronger-than-expected order book.