US STOCKS-Wall St set to open lower as tech earnings weigh
* Apple slumps after revenue forecast misses expectations
* Microsoft, Yahoo lower after results disappoint
* Thoratec jumps after $3.4 bln St. Jude deal
* Futures down: Dow 75 pts, S&P 11 pts, Nasdaq 67 pts (Adds details, comment, updates prices)
By Tanya Agrawal
July 22 (Reuters) - Wall Street was set to open lower on Wednesday as the initial optimism over earnings faded after disappointing results from technology giants including Apple and Microsoft.
Apple shares slumped 7 percent to $121.58 in premarket trading, a day after the iPhone maker's revenue forecast for the fourth quarter fell below expectations.
Microsoft fell 3.5 percent to $45.64 after reporting its biggest quarterly loss, as the company wrote down its Nokia phone business and demand fell for its Windows operating system.
Yahoo was down 2.3 percent at $38.85 after it forecast lower-than-expected revenue for the current quarter as it struggles to revive its core online advertising business. Continuación...