* Oil jumps, energy stocks lead gains on S&P
* IBM tumbles more than 7 pct after margins miss
* Lam Research forecast weighs on chip stocks
* CSX, UAL jump on strong reports, boost Dow Transports
* Dow flat, S&P up 0.3 pct, Nasdaq 0.43 pct (Updates to early afternoon)
By Sruthi Shankar
April 18 (Reuters) - Wall Street edged higher in a volatile session on Wednesday as industrial stocks gained on strong results from some marquee companies and a jump in oil prices boosted energy stocks.
The gains were kept in check by technology stocks, which were hit by a 7.6 percent slump in IBM after the company’s margins missed estimates as well as declines in semiconductor stocks.
No. 3 U.S. railroad operator CSX Corp jumped 6.3 percent after topping profit estimates. The news lifted shares other railroads and powered a 1.9 percent jump in the Dow Jones Transport index.
United Airlines gained 6.5 percent and lifted other airline stocks after reporting a better-than-expected quarterly profit, helped by higher fares.
“Even though it’s early in the earnings season, what you’re seeing is what folks were hoping — it is in line with expectations,” said Thomas Martin, senior portfolio manager at GlobAlt Investments in Atlanta.
“The growth rate is coming in slightly higher as companies report above expectations, but it hasn’t been super high.”
Earnings at the S&P 500 companies are estimated to grow 18.6 percent in the first quarter, the biggest increase in seven years, according to Thomson Reuters data.
At 12:29 p.m. ET, the Dow Jones Industrial Average was unchanged at 24,787.15 and the S&P 500 rose 0.30 percent to 2,714.53.
The Nasdaq Composite gained 0.43 percent to 7,312.41, lifted by consumer discretionary stocks including Amazon and Tesla.
Tesla rose 2.4 percent after a report that the company was aiming to ramp up production of Model 3 cars to reach its goal.
The CBOE Volatility index was up 0.51 points at 15.76, marking its first rise after closing lower for six days in a row.
Oil prices jumped about 2 percent, on a decline in U.S. crude inventories and after sources signaled top exporter Saudi Arabia wants to see crude prices closer to $100 a barrel. The S&P energy sector was up 1.6 percent and led the gainers among the 11 major S&P indexes.
Lam Research fell 4.6 percent after the chip equipment maker kept its full-year shipment forecast unchanged, which analysts said could imply a slowdown in demand.
Other chip stocks including Applied Materials and MKS Instruments also fell, and the broader Philadelphia SE Semiconductor index was down 0.5 percent.
Advancing issues outnumbered decliners on the NYSE for a 1.79-to-1 ratio, and on the Nasdaq, for a 1.77-to-1 ratio. (Reporting by Sruthi Shankar in Bengaluru; Editing by Shounak Dasgupta)