US STOCKS-Wall St edges up with Merck, IBM; Nasdaq slips with Apple
* Apple shares fall in volatile trading
* Merck on track for its best day since January 2014
* Feb U.S. single-family home prices rise
* Dow up 0.3 pct, S&P up 0.2 pct, Nasdaq down 0.04 pct (Updates to late afternoon)
By Caroline Valetkevitch
April 28 (Reuters) - The Dow and S&P 500 inched higher on Tuesday afternoon, helped by strong earnings from Merck and gains in IBM after it boosted its dividend.
IBM shares rose 1.9 percent to $174.04, breaking above the stock's 200-day moving average and giving the Dow its biggest boost. The company hiked its quarterly dividend by 18 percent, the biggest increase in five years.
Merck jumped 5.3 percent to $60.11, on track for its best day since January 2014, after reporting better-than-expected results and releasing favorable data late Monday about the safety of its Januvia diabetes drug.
Apple kept trading volatile as it swung between gains and losses a day after reporting results. The stock hit a record high in early trading but shares were last down 1.5 percent at $130.63, weighing on the Nasdaq. Continuación...