U.S. stocks posted their sixth straight day of gains on Thursday as an encouraging profit forecast from United Parcel Service lifted transportation shares, though concerns about a rise in weekly jobless claims limited the market's advance.

The Dow Jones industrial average <.DJI> added 21.46 points, or 0.19 percent, to end unofficially at 11,144.57. The Standard & Poor's 500 Index <.SPX> edged up 1.03 points, or 0.09 percent, to finish unofficially at 1,211.68. The Nasdaq Composite Index <.IXIC> gained 10.83 points, or 0.43 percent, to close unofficially at 2,515.69.

(Reporting by Leah Schnurr; Editing by Jan Paschal)