Vietnam may be a star economic performer among the nations of Southeast Asia, but for stock market investors – foreign ones in particular – it has been an easy way to lose money. Could that be about to change? At first glance, the market has been dull rather than disastrous. The Ho Chi Minh index is up 21 percent over the past five years or almost flat in terms of US dollars. The past year has seen a 6 percent rise despite the general weakness of emerging markets and meanwhile the dong has been stable on a trade-weighted basis.