The Dow Jones industrial average and S&P 500 stock index futures swung into positive territory on Tuesday following a stronger-than-expected report on July home prices.

* The S&P/Case-Shiller composite index of home prices in 20 metropolitan areas rose 1.6 percent in July from June, more than the 0.5 percent estimate forecast in a Reuters poll. The index rose 1.4 percent the month before.

* Futures suggested Wall Street would open slightly higher following Monday's gains that helped the market snap a three-day losing streak.

* S&P 500 futures rose 3.3 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 added 16 points and Nasdaq 100 futures rose 1.25 points.

(Reporting by Ellis Mnyandu; Editing by Padraic Cassidy)