Japanese shares scaled 15-year peaks on Wednesday while Hong Kong’s market leapt to seven-year highs amid speculation of more stimulus from China and Japan, as well as a delayed start to any tightening by the U.S. Federal Reserve. Just before the European open, Royal Dutch Shell (RDSa.L) said it had agreed to buy BG Group (BG.L) for 47 billion pounds ($70 billion) in the first oil super-merger in a decade. Futures were pointing to a softer opening for European stock markets, but the confirmation of the megadeal could boost sentiment.