* IBM slumps after results, biggest drag on Dow, S&P 500
* Verizon, Travelers, United Tech up after results
* Yum Brands jumps on plans to spin off China business
* Harley Davidson down on cut to shipment forecast
* Indexes down: Dow 0.12 pct, S&P 0.22 pct, Nasdaq 0.62 pct (Updates to early afternoon)
By Abhiram Nandakumar
Oct 20 (Reuters) - Wall Street was slightly lower on Tuesday as healthcare and biotech stocks fell, offsetting gains by Verizon and United Technologies.
The S&P healthcare sector fell 1.6 percent, dragged down by Allergan and Pfizer.
Verizon's shares were up nearly 2 percent at $45.49 after the largest U.S. wireless service provider reported better-than-expected revenue and profit.
The stock gave the biggest boost to the telecom sector .
United Technologies rose 5.7 percent to $97.26 after its quarterly profit beat expectations. The stock provided the biggest boost to the Dow Jones industrial average.
IBM fell nearly 6 percent to $140.57, hitting five-year lows, after it reported a bigger-than-expected fall in quarterly revenue.
"It is topline growth that is making these companies and the market see-saw back and forth as they report," said Chris Bertelsen, chief investment officer at Global Financial Private Capital.
At 12:36 p.m. ET (1636 GMT) the Dow Jones industrial average was down 20.45 points, or 0.12 percent, at 17,210.09, the S&P 500 was down 4.47 points, or 0.22 percent, at 2,029.19 and the Nasdaq composite index was down 30.31 points, or 0.62 percent, at 4,875.16.
Third-quarter company earnings are in focus this week, with investors keeping an eye on revenue growth and outlook commentary on the effects of a global economic slowdown.
S&P 500 companies are expected to show a 3.9 percent fall in third-quarter profit while revenue is expected to fall 3.8 percent, according to Thomson Reuters data.
"In the face of falling revenues, the market is going to be concerned about the next several quarters unless there can be some turnaround and resumption of growth in revenue," said John Carey, portfolio manager at Pioneer Investment Management in Boston.
Of the S&P 500 companies that have reported until Friday, 40 percent have beaten expectations on revenue, according to Thomson Reuters data. About 60 percent companies on average beat sales estimates in a quarter.
Travelers rose 2.6 percent to $109.04 after the insurer's quarterly profit topped estimates, helped by higher underwriting gains.
Harley Davidson skidded to a two-year low at $47.02 after the motorcycle maker cut its full-year shipment forecast.
Tech earnings gather steam as Yahoo and VMware report results after the close on Tuesday.
Yum Brands rose 3.7 percent to $74.34 after the fast food group said it was preparing to separate its China business.
Advancing issues outnumbered decliners on the NYSE by 1,678 to 1,262. On the Nasdaq, 1,484 issues fell and 1,194 advanced.
The S&P 500 index showed 21 new 52-week highs and three new lows, while the Nasdaq recorded 53 new highs and 34 new lows. (Reporting by Abhiram Nandakumar in Bengaluru; Editing by Don Sebastian)