2. Cypress Semiconductor Corp.
What: The San Jose-based company is one of the largest makers of SRAM, a memory chip that is used in consumer electronics.
Market cap: $3.8 billion
Recent news: The firm is pushing car makers to incorporate its chips, with applications including wireless radios and touch displays.
3. Brocade Communications Systems
What: The San Jose-based firm supplies enterprise networking hardware.
Market cap: $3.62 billion
Recent news: In May, Brocade acquired wireless network equipment maker Ruckus Wireless Inc. for $1.5 billion. It's Brocade's latest efforts to tap into the growing Wi-Fi market.
Fitbit Inc.
What: The San Francisco-based company makes fitness wristbands, which keep track of users' steps, activity, sleep, and heart rate throughout the day.
Market cap: $3.28 billion
Recent news: Fitbit wants to broaden its appeal beyond the consumer wearables market. The company is pushing hard into healthcare, though it has faced criticism for the trackers' "wildly inaccurate" heart-rate readings. Fitbit recently received a favorable ruling from the US International Trade Commission in response to accusations by competitor Jawbone for allegedly stealing its trade secrets.
Yelp Inc.
What: The San Francisco-based company operates an online platform that provides customer reviews.
Market cap: $2.93 billion
Recent news: Yelp just got out of a libel lawsuit brought by a small business owner who had received negative reviews on the service. It wasn't held liable because users, and not the company, produced that content, the San Francisco Business Times reported.
FireEye Inc.
What: A cybersecurity firm based in Milpitas, California that detects advanced hacking attacks.
Market cap: $2.43 billion
Recent news: The firm hired Morgan Stanley to field dealmaking interest and was said to have turned down several takeover offers earlier this year, according to Bloomberg News.