Updated from 4:06 p.m. EDTStocks leapt in the final hour of trading Tuesday, shrugging off earlier uncertainty amid Fed Chairman Alan Greenspan's comments on tight supplies of natural gas. Rallying more than 60 points in the last hour, the Dow Jones Industrial Average ended up 74 points, or 0.8%, at 9054, while the Nasdaq gained 23 points, or 1.5%, to 1627. The S&P 500 rose 8 points, or 0.9%, to 984. Greenspan told a House panel regarding gas prices, "We are not apt to return to earlier periods of relative abundance and low prices anytime soon." Greenspan stressed that as with crude oil, American markets need unlimited access to natural gas in order to thrive, sounding a cautious note that temporarily cooled a market rally. But price action was mostly positive on Tuesday, and bullish sentiment surfaced in the final hour. Traders are expecting volatility in coming sessions, reflecting investors' ambivalence over keeping the rally going and taking profits during the second-quarter preannouncement season. Going by recent warnings, it is possible that upcoming earnings won't be overwhelmingly positive, and that the market is due for a breather. "I think we're in early stages of building near-term top in market," said Ken Tower, market strategist for CyberTrader. "Friday morning we were up sharply, but by afternoon we had given it all back. That probably signals the end of the terrific uptrend seen since March 12. Over the next few days, we'll back ... and eventually head into some decline that takes us back around the mid-May lows. That's a standard reaction to such a sharp advance. Long-term we're in good shape. In the next month, we're in some trouble." While data were scarce Tuesday, bulls took heart in the Blue-Chip Economic Indicators survey, a poll of 53 economists, which forecast that GDP will grow 2.4% in 2003, up from 2.3% in May. Nokia ( NOK) said Tuesday that its second-quarter sales could be at the low end of expectations because of a sluggish economy, a weak dollar and the SARS virus. But the world's largest handset maker stuck to previous earnings estimates and provided a fairly bullish outlook for its network segment. Analysts reacted negatively to the news, with Wells Fargo Securities downgrading it to sell from hold, with a $12 price target. The news comes a day after Motorola ( MOT) warned that sales and earnings for the quarter would fall short of expectations. Nokia's American depositary shares fell 25 cents, or 1.4%, to $17.71. Some of Nokia's peers were gaining, including network giant Ericsson ( ERICY), which added $1.02, or 9.9%, to $11.35. While most companies are just entering the preannouncement season, one is ahead of the game with earnings results Tuesday. Homebuilder Lennar ( LEN) is expected to report a profit of $1.69 a share in its second-quarter results after the close. Lennar shares gained $2.49, or 3.7%, to $69.75. Ahead of the report, Lehman Brothers raised its price target on the company to $80 from $65. Lehman was also upbeat on other homebuilders, such as Centex ( CTX), KB Home ( KBH), Pulte Homes ( PHM) and Toll Brothers ( TOL). The Dow Jones Home Construction Index gained 3.3%. Kmart ( KMRT), which just emerged from bankruptcy a month ago and began trading at $14 as an over-the-counter stock, extended its rally on its first day of trading on the Nasdaq, gaining $1.90, or 10.7%, to $19.60. Blue-chip Wal-Mart ( WMT) announced plans to launch an online DVD rental service that would cost $15.54 a month, undercutting pioneer NetFlix ( NFLX) by more than $4. NetFlix shares fell 30 cents, or 1.3%, to $22.70, while Wal-Mart gained 97 cents, or 1.8%, to $54.76.