The 16 industries that have made America's richest people, from tech to trucking

Finance and technology usually spring to mind when thinking of the world's most lucrative industries.

And that's for good reason. They have been the source of wealth for nearly half of America's 400 richest people, as ranked and categorized by Forbes.

However, billion-dollar fortunes have been made in other sectors, too, ranging from trucking to pest control.

Business Insider has compiled data from the 2026 Forbes 400 list, which is an estimated snapshot of the 400 richest people in America as of September 4.

Forbes estimated each member's net worth using a variety of sources, including interviews, asset valuations, and deductions for debt, charitable contributions, and fund donations.

The following ranking is based on the 16 industries into which Forbes categorized each individual. Business Insider calculated how many individuals went into each category to find which industries have minted the most of America's richest people. It also compiled the richest person within each industry.

Some of the members featured an "& family" tag, which means wealth held by a founder or heir's immediate family. The totals, therefore, count Forbes entries, not necessarily individual people.

Here are the industries that featured the most on the Forbes 400 list, from most to least prevalent.

The finance and investments industry has been the biggest maker of fortunes. Most of the wealthiest individuals in this category are founders of hedge funds, mortgage lenders, VC, and investment firms.

Some are heirs to founders, such as the grandchildren of Fidelity founder Edward Johnson II.

Technology has been a massive maker of fortunes; the nine richest in this category are wealthier than Warren Buffett.

Many are founders of big-name tech companies, as well as software and computer hardware firms. The AI boom has brought several newcomers to the list, including OpenAI cofounder and president Greg Brockman.