In the early 1980s at&t Corporation, then America’s telecoms monopoly, was the darling of Wall Street. As big tech of the day, it was the mightiest company in the s&p 500, accounting for 5.5% of the blue-chip index’s total market value. 

Today its largest descendants, at&t and Verizon, can only dream of their parent’s former glory. The two companies make up less than 0.7% of the index—and falling. Their combined market capitalisation of $250bn is roughly half what it was at the start of 2020; the s&p 500 is up by more than two-fifths since then (see chart).