When people think of the largest companies in Silicon Valley, computer and digital giants such as Apple (AAPL), Alphabet/Google (GOOGL), and Facebook (FB) are the first that come to mind. However, successful public companies within Silicon Valley extend beyond the technology sector—especially if you extend the traditional Silicon Valley borders a bit to the north and northeast to include Contra Costa County and the city of San Francisco itself.

If you do, you can count Wells Fargo & Co. (WFC), Visa, Inc. V) and Chevron Corporation (CVX), as non-tech, multinational majors firms that all have their headquarters in Silicon Valley.

Let's look at the Big Six of Silicon Valley, incorporating three traditional types of public companies (that is, high-tech) and three non-tech (from other sectors). All data is current as of April 21, 2020.

key takeaways

  • While best-known as a center of the high tech sector, Silicon Valley is actually home to all sorts of corporate giants.
  • The Big Six of Silicon Valley firms consist of three tech firms—Apple, Alphabet (Google), and Facebook—and three in other industries: Visa, Wells Fargo, and Chevron.

1. Apple

Ah, the golden Apple. One of the most successful companies on the planet, it makes its headquarters in the heart of the Valley: Cupertino, in Santa Clara County. The company has a current market cap of $1,174 billion and a price-earnings (P/E) ratio of 21.20.

Apple designs, manufactures and sells mobile devices, personal computers, and digital music players, and it also sells numerous related software, services, networking solutions, and digital content and applications. The company's primary products include the iPhone, iPad, and Mac computers—along with the operating system software and application software to run them. In 2019, it also entered the fields of entertainment streaming services (with Apple TV+) and financial services (with the Apple Card).

2. Alphabet/Google

Alphabet Inc. is the holding company of Google, the most widely used internet search engine in the world. It has a current market cap of $833 billion, giving the company a P/E ratio of 24.65.

The company has reached success on a massive scale since its inception and has business units that go beyond its search capabilities. It now offers a range of products and services across multiple screens and multiple device types, from browsers like Chrome to phones like Android to the G Suite of cloud-based word-processing apps. Google is headquartered in Mountain View, in Santa Clara County.

Its products and services are offered in more than 50 countries in more than 100 languages. However, the company's biggest moneymaker is its offering of brand advertising and performance advertising. Google offers a self-serve platform for advertisers, agencies, and publishers allowing them to power their digital marketing across desktop display, mobile, and video.

3. Facebook

Facebook is arguably the world's original social networking company; it's certainly one of the most successful. Based in Menlo Park, in San Mateo County—the geographic center of the Valley—the company has a current market cap of $488 billion and a P/E ratio of 26.57. 

Facebook was launched in 2004 by Mark Zuckerberg as a college social networking website, but it has since expanded to allow any person above the age of 13 to create a social profile. The company boasts literally billions of users, connecting them through posts, messages, status updates, photo and video sharing, and notification updates. The massive scale of the company has allowed it to offer highly targeted advertising, resulting in billions of dollars in annual revenue and, of late, some controversy.

4. Wells Fargo

Wells Fargo breaks the Silicon Valley mold in a couple of ways. For one thing, it wasn't born around the turn of the 21st century or even the 20th century. For another, its field isn't technological, but financial.

Headquartered in San Francisco, Wells Fargo was founded in 1852 (two years after California became a state) and, after a series of mergers with other regional banks on both coasts, has grown to become the third-largest bank in the United States in terms of assets. It is one of the largest U.S. banks by market cap, which is currently $110 billion. Its P/E ratio is 9.48.

Technically, Wells Fargo is a holding company that consists of three banking and financial services subsidiaries: community banking, wholesale banking, and wealth and investment management. Although plagued by a series of consumer-abuse scandals throughout the 2010s, resulting in the payment of billions in penalties, the financial institution still clocked $85 billion in revenues on its 2019 annual income statement.

5. Visa

Known for its ubiquitous credit cards, Visa is another multinational financial services company based in Silicon Valley. The company moved its headquarters to Foster City, in San Mateo County in 2012. Its current market cap is $356 billion, and its current P/E ratio is 29.29.

Visa doesn't actually issue cards or extend lines of credit; instead, it provides banks, credit unions, and other financial institutions with products (i.e., credit or debit cards) that they can offer to their customers. Technically speaking, it's a retail electronic payment network that specializes in the facilitation of funds transfers through its credit card and debit card services.

6. Chevron

Chevron is a bit of an outlier in our group, both figuratively—it's the sole energy company—and literally: Its HQ is in San Ramon, in Contra Costa County (a bit north of the Valley proper). The company has a current market cap of $152 billion and a current P/E ratio of 54.07.

Like Wells Fargo, Chevron is a corporation with roots reaching back to the 19th century. Incorporated in 1906, it has grown from a small oil refiner into a multinational energy giant. Also like Wells Fargo, Chevron is technically a holding company made up of upstream and downstream segments. Upstream deals with crude oil and natural gas exploration and production; Downstream with the refining of crude oil into petroleum products, and the subsequent marketing of them. Combined, these segments combine to give Chevron control of the entire supply chain of energy.