US STOCKS-Wall St dips on earnings, but set to end week strong
* Indexes on track to break three-week streak of losses
* UPS shares fall after outlook, Starbucks up on results
* Oil falls, on track for another negative week
* Dow, S&P 500 down 0.3 pct, Nasdaq up 0.1 pct (Updates to market open)
By Ryan Vlastelica
NEW YORK, Jan 23 (Reuters) - U.S. stocks fell modestly on Friday, pressured by some disappointing results from major multinational companies which offset optimism triggered by the European Central Bank's recent decision to buy bonds and boost euro zone growth.
Wall Street jumped on Thursday, with the S&P 500 and Nasdaq returning to positive territory for the year, after the ECB detailed a bigger-than-expected bond-buying program to lift the region's sagging economy and fight deflation.
With the ECB stimulus details known, U.S. corporate earnings will likely be the primary driver of trading over the next few weeks. A number of bellwether names have already disappointed, with revenue being a particular area of concern.
United Parcel Service Inc gave a fourth-quarter earnings outlook that was below expectations, citing a disappointing performance in U.S. domestic ground shipments. Shares slumped 9.7 percent to $103.21. Continuación...