CNBC has a daily feature called after-hours buzz that, it being earnings season, is full of corporate quarterly reports. And lately the same story has been repeated: decent earnings but weak sales and/or disappointing guidance. Here’s today’s list:

AT&T topped analysts’ profit estimates by a penny on Wednesday, but revenue came in light as core subscribers declined. Shares rose about 2 percent after the announcement.

EBay shares increased after it handed in earnings and sales figures that beat estimates, boosted by transaction growth and corporate cost control.

Social media giant Facebook reported profit that topped estimates, but revenue missed. However, the company said its monthly user base is now larger than China’s population. The stock tumbled about 3 percent.

Chip maker Qualcomm beat on the top and bottom lines, but guidance came in light of analyst estimates. Shares fell about 2 percent in extended trading.

Texas Instruments shares fell nearly 8 percent after it missed earnings and revenue forecasts. It also reported second-quarter guidance that trailed estimates.

Why is this pattern important? Because earnings are easy to manipulate through share buybacks, write-offs and reserve changes, while sales are tougher to lie about. So if revenue is the important number, the portrait of corporate health now being painted is pretty bleak. Earnings can’t continue to grow indefinitely if sales are falling, and sales are weak for what seems like the majority of reporting companies.

Share prices, of course, depend (again in the long run) on underlying profits. So if sales growth doesn’t support rising earnings, then earnings won’t support rising — or even stable — share prices. This has yet to sink in with investors, for a variety of reasons. But eventually the math will become inescapable.