The Dow Jones Industrial Average was tipping lower in early trade Thursday, with declines in shares of Walmart Inc. and Cisco Systems Inc. producing the stiffest headwinds for the blue-chip gauge. Shares of Walmart were down even as the giant retailer earlier in the premarket reported first-quarter earnings and sales beat expectations. Meanwhile, Cisco’s stock was under pressure after services revenue at the networking giant fell short of Wall Street expectations. Cisco, down 3.8%, or $1.73, and Walmart declining by 1.6%, or $1.37, were combining to exact a 20-point toll on the price-weighted average. A $1 move in any one of the Dow’s 30 components equates to a 6.89-point swing. Most recently, the Dow was off 0.3%, or 80 points, at 24,691, while the S&P 500 index was down 0.1% at 2,718 and the Nasdaq Composite Index was down 0.2% at 7,386.