Updated from 4:08 p.m. EDTStocks in the U.S. ended lower Wednesday as a downturn in chip shares and transports more than offset the gains recorded by retailers and homebuilders. The Dow Jones Industrial Average lost 79.26 points, or 0.6%, to 13,968.05, and the S&P 500 was down 7.04 points, or 0.5%, at 1539.59. The Nasdaq was off 17.68 points, or 0.6%, at 2729.43. Leading the way lower was a 2.1% drop in the Philadelphia Stock Exchange Semiconductor Sector index. Among the weakest names was Micron ( MU), which fell 9% on the heels of its quarterly loss that was announced following the previous close. Also hurting the group were declines of 2% in Intel ( INTC) and 4% in Nvidia ( NVDA), who were started with underweight ratings at Morgan Stanley. Morgan gave the same treatment to Advanced Micro Devices ( AMD), but that stock ticked higher. The firm was kinder to Altera ( ALTR), PMC Sierra ( PMCS) and ON Semiconductor ( ONNN), upgrading each to overweight from equal weight, but the individual stocks were mixed nonetheless. Elsewhere, the Dow Jones Transportation Average surrendered 1.5%, owing to selloffs in Overseas Shipholding ( OSG), CSX ( CSX) and C.H. Robinson ( CHRW). While both the Philadelphia Housing Sector index and the S&P Retail index advanced roughly 0.9%, it wasn't enough to overcome the broader selling pressure on the market.