HONG KONG (Reuters) -Economic policy shift in China and the investment opportunities it is creating are drivers for long-term bets in the country by global asset managers, top executives said on Wednesday. "China is the world's second-largest capital market" after the U.S., the head of BlackRock's global client business, Mark Wiedman, said at the Global Financial Leaders Investment Summit in Hong Kong. "Long term, (China) has to be part of a global investment portfolio."