The Dow Jones Industrial Average on Friday was gaining to close out a mostly downbeat trading stretch, but the gains don't appear to be sufficient for the blue-chip to avoid its longest weekly string of losses in about eight years. The Dow DJIA, +0.19% was set for a weekly decline of 0.5%, even as the benchmarks rose 150 points, or 0.6%, at 25,640. If the gauge logs a weekly loss it would be its fifth straight, representing the longest such weekly skid since a six-week slump ended June 10, according to FactSet data. Meanwhile the S&P 500 index SPX, +0.29% was trading 0.6% higher, on track for a weekly slump of 0.7%, while the Nasdaq Composite Index COMP, +0.36% gained 0.8% at 7,689, but set for a weekly decline of 1.6%. Both indexes are on track for their third straight weekly declines.