US STOCKS-Futures flat with S&P near all-time high
* S&P 500 coming off all-time closing high, targeting record intraday high 1,576.09.
* Further gains may be tough to come by
* ISM manufacturing data on tap after market opens
* Dow down 17 pts, S&P down 1.1 pt, Nasdaq up 0.25 pt
By Ryan Vlastelica
NEW YORK, April 1 (Reuters) - U.S. stock index futures were flat on Monday, with investors looking for reasons to keep pushing shares higher after the S&P 500 closed at a new all-time high.
* Equities have been on a tear in 2013, with stocks jumping 10 percent in the first quarter, extending their monthly string of gains to five. With the advance, the S&P is only a few points away from its all-time intraday high level of 1,576.09.
* While market momentum has been positive, many investors have been calling for a near-term pullback, saying shares have become over-extended.
* Investors will also look ahead to the U.S. Institute for Supply Management's March reading on manufacturing activity at 10 a.m. (1400 GMT), with the main index expected to come in at 54.2, same as the prior month. February construction spending, which is also scheduled for release at 10 a.m., is seen rising 1 percent, compared with a 2.1 percent drop in January. Continued...