SINGAPORE, Aug 16 (Reuters) - HSBC (HSBA.L) said on Monday it had agreed to acquire Axa"s (AXAF.PA) insurance assets in Singapore for $575 million as it scales up its insurance business. "The proposed acquisition, which is subject to regulatory approval, is a key step in achieving HSBC"s stated ambition of becoming a leading wealth manager in Asia, by expanding its insurance and wealth franchise in Singapore, a strategically important scale market for HSBC, and a major hub for its ASEAN wealth business," HSBC said in a statement.