* Apple rallies after results, boosting tech names
* Boeing falls despite profit rise, weighing on Dow
* Biotechs rally for fourth straight session
* Dow down 0.1 pct, S&P up 0.2 pct, Nasdaq up 0.4 pct (Updates to afternoon trading)
By Ryan Vlastelica
NEW YORK, July 23 (Reuters) - U.S. stocks were largely higher on Wednesday, with the S&P 500 hitting another record high after bullish results from tech giants Apple and Microsoft, though technical resistance and conflicts in Ukraine and the Gaza Strip kept gains in check.
Biotech stocks were among the biggest gainers of the day, boosted by some strong results and drug trial data. The Nasdaq Biotech index jumped 1.9 percent in its fourth straight day of gains.
The S&P information technology index rose 0.3 percent, one of the strongest sectors of the day. Apple Inc and Microsoft Corp rose following results posted late Tuesday, with Apple up 3 percent to a 22-month high as concerns faded about the iPhone maker's margins.
Dow component Microsoft was up 0.3 percent after it said it aimed to get its loss-making Nokia phone unit to break even within two years.
"Earnings season has been going very well, beating on both the top and bottom line, which suggests companies will continue to execute well," said Alan Gayle, senior investment strategist at RidgeWorth Investments in Atlanta, Georgia.
About 68.5 percent of S&P 500 components have reported earnings above expectations, topping the long-term average of 63 percent, according to Thomson Reuters data. On the revenue side, 63.1 percent have beaten, above the historical average of 61 percent.
Overseas issues continued to limit market gains. Two Ukrainian fighter jets were downed near the area where a passenger jet was shot down last week, a spokesman for Ukraine's military operations said Wednesday.
Violence also continued in the Gaza Strip, though U.S. Secretary of State John Kerry said indirect truce talks between Israel and Hamas had made some progress.
"There's a battle going on in the market between earnings and geopolitical issues, and right now it looks like earnings have a slight edge," said Gayle, who helps oversee $50 billion in assets. "These are big areas of concern, but they've yet to translate to anything tangible from an economic standpoint."
The Dow Jones industrial average fell 17.18 points or 0.1 percent, to 17,096.36, the S&P 500 gained 4.58 points or 0.23 percent, to 1,988.11 and the Nasdaq Composite added 18.40 points or 0.41 percent, to 4,474.42.
The S&P touched a record above 1,989 but the 1,985-1,990 area was developing into technical resistance, analysts said.
The Dow was kept under pressure by Boeing Co, which fell 2.2 percent to $126.86. It reported a 52 percent jump in quarterly profit but investors were spooked by rising costs in its military tanker program.
PepsiCo rose 2.9 percent to $91.76 after it reported a higher-than-expected quarterly profit and raised its full-year adjusted earnings forecast.
In the biotech space, Biogen Idec reported sharply higher-than-expected quarterly revenue on surging sales of its new treatment for multiple sclerosis and raised its full-year profit forecast. Shares were up 10.9 percent at $336.93.
Intuitive Surgical rose 14.7 percent to $449.98, the S&P's biggest percentage gainer, a day after second-quarter revenue beat expectations.
Puma Biotechnology nearly quadrupled to $233.28 on heavy volume a day after it said its experimental breast cancer drug met its main goal in a late-stage trial. (Editing by Bernadette Baum and Nick Zieminski)