NEW YORK, Sept 28 (Reuters) - U.S. stocks index futures extended gains on Tuesday after data showed home prices declined slightly in July and were seen stabilizing.
S&P 500 futures rose 4 points and were above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures gained 30 points and Nasdaq 100 futures added 9 points.
The S&P/Case-Shiller composite index of 20 cities declined 0.1 percent in July from June on a seasonally adjusted basis, as expected. Unadjusted, the index gained 0.6 percent, more than the 0.4 percent forecast increase.