Could Intel survive without Apple as a big customer?
Investors aren't so sure.
Shares of Intel nosedived more than 8% Monday on a report that Apple plans to start making its own processors for Mac computers as early as 2020. The stock closed down 6%.
The move is part of a larger strategy to ensure all Apple devices function similarly and can work in tandem, according to Bloomberg.
Apple began using Intel processors in Macs in 2006. Paul Otellini, who was CEO of Intel at the time, appeared on stage with Steve Jobs in a cleanroom suit to announce the partnership.
Since then, Intel has come to count on sales to Apple.
Intel still makes most of its money from selling processors for PCs, according to Joseph Unsworth, a semiconductor analyst at research firm Gartner. And Mac computers are a major part of that market, he said.
Apple made up roughly 7% of the PC market in the fourth quarter of 2017, according to data from a February 2018 Gartner report.
Intel is already dealing with slumping personal computer sales in general. Gartner expects the PC market to grow 0.8% in 2018 - but that would be the first year that PC sales rose since 2011.
The company has been diversifying its business to try to head off this trend. The company has been investing in artificial intelligence and self-driving car technology. It's also focused on selling processors for computer servers.
But the PC market remains important.
"It's still the largest category [as far as] revenue," Unsworth said.
Intel said the company does not "comment on speculation about our customers." Apple did not immediately respond to a request for comment.
-- CNNMoney's David Goldman contributed to this report.