WASHINGTON (MarketWatch) - Sentiment among U.S. home builders retreated in June after a tax break for home buyers expired, according to a monthly survey released Tuesday by the National Association of Home Builders. The housing market index dived to 17 in June from 22 in May, the NAHB reported. All three components of the index fell in June, and home builders were more discouraged in all four regions of the country. The index was lower than the 21 that was expected by economists surveyed by MarketWatch, and was the lowest since it hit 15 in March.