The stock market fell sharply on Monday, with intraday losses of as much as 750 points for the Dow Jones Industrial Average and similarly sized percentage drops for the other major benchmarks. A host of negative factors hit some key areas of the market that until now had been leaders, and investors as a result started to assess more seriously the possibility that the 9-year-old bull market might be getting long in the tooth. Political pressure on social media and e-commerce stocks played a role in the rout, but some other companies found themselves on the losing end as well. Intel (INTC -5.42%), Tesla (TSLA -4.02%), and Delta Air Lines (DAL 1.16%) were among the worst performers on the day. Here's why they did so poorly.

Intel outside?

Shares of Intel dropped 6% after the chip giant got bad news regarding one of its key supply customers. Intel has been providing processors for various Mac products from Apple (AAPL 0.06%), but some now believe that Apple will shift production of Mac chips in-house within the next couple of years. The change could happen as soon as 2020, and although the initiative is in its early stages, Apple's move could be a harbinger of similar strategic decisions from other manufacturers of computers and mobile devices. Intel will have to find ways to pivot and make itself indispensable in order to fight back.

Carpeted room with six chairs in front of curved wall with Intel logo and blue lighting.

Image source: Intel.

Tesla hits the brakes

Tesla stock fell 5% in the aftermath of several news items. Many followers of the stock reacted negatively to a tweet from CEO Elon Musk apparently making light of the electric-auto maker's debt situation. Yet more substantive were Tesla's interactions with the National Transportation Safety Board following a recent Model X crash, as well as worries about whether mass-market Model 3 production will pick up as fast as necessary. The stock's decline reflects the fact that Tesla is priced for near-perfection, and even small hiccups could translate to bigger problems if they're not remedied quickly.

Delta flies lower

Finally, shares of Delta Air Lines sank 5%. The Department of Transportation has been weighing access to the Cuban capital of Havana, with substantial competition looking to get only fiercer going forward. In a tentative DoT decision, Delta was given the right to operate a second daily flight from Miami to Havana. However, competitors were also given greater penetration into Cuba, including American Airlines and its five daily roundtrips between the two cities. With a shrinking number of major players in the industry, discussions of specific city-pair routes like these could become increasingly important for Delta and its peers going forward.