Some big-cap telecom and cable companies are lagging in IBD’s accumulation/distribution ratings as institutions sell those shares amid stock-market volatility. IBD’s accumulation-distribution rating tracks the relative degree of institutional buying (accumulation) and selling (distribution) in a particular stock over the past 13 weeks. It appears in IBD’s daily research tables, stock checkup at Investors.com and in charts accompanying the IBD 50 and Big Cap 20. A rating of A or B indicates that funds are buying, or accumulating, the stock. A C rating is neutral, and a D or E indicates net selling, or distribution. Many telecom and cable companies have E ratings. They include AT&T (T), Akamai Technologies (AKAM), Charter Communications (CHTR), Comcast (CMCSA), Dish Network (DISH), T-Mobile US (TMUS), Time Warner Cable (TWC), Verizon Communications (VZ) and Vodafone (VOD). In the wireless industry, there’s concern over a price war that has erupted as subscriber growth slows. Tablet computer users now account for most new subscriber additions. Heading into Q3 earnings results, investors are also waiting to see how Apple’s (AAPL) launch of the iPhone 6 has impacted subscriber turnover and mobile phone upgrades at AT&T, Sprint (S), T-Mobile and Verizon. Europe’s slowing economies amid fierce wireless competition, meanwhile, have taken a toll on Vodafone’s stock.