Shares in the two companies, which both sell watches, have gotten crushed this year, each dropping 35 percent. They're two of the three worst performers in the S&P 500, with coffee company Keurig Green Mountain down the same amount.
Welcome to the world of the Apple Watch and a whole new category of companies threatened by the technology giant.
Read MoreHere's why Kors crumbled
Watches account for three-quarters of Fossil's revenue. And since 2004, Fossil has been the exclusive manufacturer of watches for Kors, which sells the timepieces for $195 to $550 a pop.
Apple said on Thursday that the Apple Watch, which started selling online in April, will hit retail stores June 26. At the same time, the devices will be available to Web shoppers in Italy, Mexico, Singapore, South Korea, Spain, Switzerland and Taiwan.
Whether or not the Apple Watch eventually becomes as dominant as the iPod or iPhone, it's already having a clear impact on the financial markets. It's not just Apple. Companies such as Samsung, Motorola, LG and Pebble are bolstering their own lines of smartwatches.