The Chinese are getting richer. Last year, the number of millionaire households in China was 4 million, as 1 million were added to the total. It was the second-highest total of rich households after the U.S., with 7 million, says a study by the Boston Consulting Group. For Noah Holdings (NOAH), it’s a favorable trend. The company is a wealth manager based in Shanghai with more than $12 billion in assets under management.