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Amid the stock market’s chaos, order sometimes emerges.

To anyone with an eye on cable television and movie stocks this week, the $53 billion erased in market value may have struck a chord. It’s the same market value that was created in Netflix Inc. and Amazon.com Inc. in the last month.

Coincidence or not, there’s a symmetry to it that underlines how the model that drives sales at TV giants like 21st Century Fox Inc. and CBS Corp. has been threatened by online providers, which include Netflix and Amazon.

“If you take a long-enough step back there is a logic and rhythm to the markets,” said Jim Dunigan, the 62-year-old chief investment officer at PNC Bank NA in Philadelphia, which oversees $135 billion. “If the slope of earnings with general media companies is flattening out a bit, it wouldn’t be unnatural to seek out growth in companies like Netflix or Amazon.”

Dragged down by concern their revenue is at risk, the 15-company Standard & Poor’s 500 Media Index tumbled 8.2 percent Wednesday and Thursday, the biggest slump since 2008, after a

0.1 percent drop on Tuesday. The drop erased 2015’s gains for a group that has posted annualized returns of more than 33 percent since 2009.

CBS and Fox failed this week to allay investor concerns over the health of the pay-TV industry, reporting quarterly earnings marked by shrinking U.S. ad sales.

“The big driver to this over the last several years has been that eyes are moving to digital and online,” Jason Benowitz, a New York-based senior portfolio manager at Roosevelt Investment Group Inc., said by phone. “We’ve gotten disappointments from cable networks’ advertising and it’s probably because those dollars are flowing to companies like Netflix and Amazon.”