New York - US stock index futures kicked off the third quarter with early gains Tuesday, buoyed by a report showing China's factory sector expanded in June for the first time in six months, and ahead of US data expected to show manufacturing continued to grow.

* China's final reading of the HSBC/Markit purchasing managers' index (PMI) for June rose to 50.7 from May's 49.4, edging past the 50-point level that separates growth in activity from contraction for the first time since December.

* Both Markit's and the Institute for Supply Management's measures of factory activity in the United States are due later in the day, at 9:45 a.m. EDT (15:45 SA time) and 10:00 a.m. (16:00 SA time) respectively.

Car sales are also due throughout the day.

* S&P 500 e-mini futures were up 4 points and fair value - a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract - indicated a higher open.

Dow Jones industrial average e-mini futures rose 40 points and Nasdaq 100 e-mini futures added 11 points.

* Manufacturing in Japan, the world's third-biggest economy, also gained pace in June, fueled by improving demand at home, but euro zone growth faltered as Germany, the region's top economy, slowed.

* AT&T said on Monday it sold its equity in America Movil for $5.57 billion to a company controlled by Carlos Slim, allowing the billionaire to tighten his grip on the giant Mexican telecoms company.

AT&T said in May it would sell its stake to help it gain regulatory approval for its purchase of DirecTV.

* Amicus Therapeutics shares rose 9.3 percent in premarket trading after positive research notes, including an upgrade to outperform at Leerink, where the stock's price target was raised to $6 from $2.50. - Reuters