Stock prices for many companies headquartered in the Tri-Counties fell June 24 as investors reacted to Britain’s vote to leave the European Union.

Thousand Oaks-based biotech giant Amgen dropped $5.82 or 3.82 percent. Two other companies based in Thousand Oaks, Teledyne and Inphi, saw stock prices decline $5.72 or 5.66 percent and $3.44 or 10.52 percent, respectively.

Two Goleta-based companies experienced sharp drops as well with Deckers Outdoor down $1.94 or 3.36 percent and AppFolio down 77 cents or 5.22 percent. MindBody of San Luis Obispo ended 50 cents lower or 3.35 percent and CalAmp of Oxnard fell 81 cents or 5.41 percent.

It was not all doom and gloom. Two tri-county companies had big gains June 24, with Interlink Electronics of Camarillo up $1.86 or 16.61 percent and Stellar Biotechnologies of Port Hueneme up 61 cents or 15.6 percent.

The U.S. has weathered drastic volatility before and the market has time to adapt in the two-plus years the deal will take to finalize, said Bill Watkins, executive director of the California Lutheran University Center for Economic Research and Forecasting. The abrupt decline is an overreaction, he said.

“I would be surprised if this was the start of a significant downward trend,” Watkins said. “I don’t expect much to change.”

Global markets buckled as the “Brexit” drove the pound to the lowest in more than 30 years and wiped about $3 trillion from stock market values while sparking demand for haven assets from U.S. Treasuries to gold.

The Dow Jones Industrial Average sank more than 600 points, or 3.7 percent, to erase gains for the year, while European stocks slid 7 percent in their worst day since 2008. Volume in U.S. trading topped 13 billion shares, the most this year.

• Staff writer Alex Kacik and Bloomberg News contributed to this report. Contact Glenn Rabinowitz at grabinowitz@pacbiztimes.com.