Jeff Yass, head of Susquehanna International Group and the richest man in Pennsylvania, according to Forbes, collected an average of $1.3 billion a year in annual income from 2013-18, the sixth-highest income of all Americans, according to tax records collected by ProPublica, a nonprofit reporting enterprise.

Only five other Americans earned more. They were Microsoft founder Bill Gates, digital finance mogul and former New York mayor Michael Bloomberg, WhatsApp founder Jan Koum, Apple founder Steve Jobs’ widow Laurene Powell Jobs (a Penn grad), and Ken Griffin, founder of Citadel, a Susquehanna rival among the major Wall Street trading and investment firms.

Yass paid 18.7% of his earnings in federal income taxes, according to ProPublica. That’s about the same as Gates, and less than Koum or Griffin, but more than Jobs or Bloomberg. ProPublica did not look at state and local taxes. It’s also below the top rates the IRS levies on wages and other personal cash income, which in 2018 topped out at 37% for married people filing jointly and making more than $600,000.

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But many of the rich pay taxes mostly on capital gains, which are typically taxed at lower rates than wage income, ProPublica noted. Yass also shielded less of his income from taxation — about 4%, compared with 66% for Bloomberg or 51% for Jobs, who give a lot of their money to nonprofits.

Susquehanna and Yass did not immediately respond to a request for comment by The Inquirer.

Locally, Yass is a well-known political donor, directly or through political-action committees such as the Club for Growth giving to candidates including former President Donald Trump, past Philadelphia mayoral hopeful Anthony Williams, a Democrat, and U.S. Senate hopeful William McSwain, a Republican and former U.S. attorney under Trump. Yass has also supported Libertarian candidates and libertarian-leaning U.S. Sen. Rand Paul (R., Ky.).

Yass and his wife, Janine, have been strong supporters of private and charter schools. He has backed pro-private school efforts and political leaders in the U.S. and Israel, two countries where Susquehanna has significant operations. He keeps a low public profile, seldom discussing his financial and political investments in the media.

Susquehanna was started on the floor of the Philadelphia Stock Exchange in the mid-1980s by Yass and a group of fellow SUNY-Binghamton graduates who studied gambling odds and applied the lessons to securities markets. The company’s headquarters is on City Avenue in Bala Cynwyd and it has offices around the world.

The firm is well-known on Wall Street as a leading “proprietary trader,” investing its partners’ own money, mostly, rather than for clients. The firm has a long history of shifting focus among different kinds of stocks, bonds, and other investments and different parts of the world over the years, as Yass and his partners sniff out high profits from high-volume trading, varying from tech stocks to commodities, junk debt to municipal bonds, in different periods.

Since the 1990s, Yass’ firm and his current and past partners have invested trading profits in hundreds of small software and technology companies around the world, from health tech start-ups in Chester County to the China-based company that owns the popular TikTok social media site.

TikTok holding company ByteDance ranks among Yass’ most valuable investments — though it’s unclear how the billions in presumed market value Yass and other Susquehanna-related investors in that firm have gained in recent years can be easily repatriated to the U.S. That’s because the company remains non-public and is managed under China’s tight tech regulatory regime.

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Susquehanna has fought the IRS over profits it hopes to distribute to its partners. In 2020, the Supreme Court declined to hear a Susquehanna affiliate’s appeal of part of a $380 million tax charged levied on one of its affiliates over profits earned from a loan by a foreign partnership the company had organized, capping six years of litigation.