Concerns about a top rival's performance put big telecoms Verizon (VZ -2.11%) and AT&T (T -2.67%) in the investor doghouse on Friday. The stocks of both companies traded limply, to the point where the pair closed the day more than 2% lower in price. That made them outliers, as the S&P 500 index inched 0.6% higher. Rather uncomfortably, both stocks are components of the index.A peer disappointsThe aforementioned peer is T-Mobile US (TMUS -11.26%), which published its first-quarter results after market close ...