Steyer is a wealthy hedge fund manager and top-Democratic donor who runs an environmental group called NextGen Climate.

Thomas Steyer, photo courtesy of Aspen Institute

In introducing Steyer, Eric Bauman, the vice chairman of the state party, touted Steyer’s spending in Democratic politics, particularly for two initiatives in Los Angeles County that helped register Latinos as Democrats.

Bauman called Steyer a “champion” for being “willing to invest (his) personal wealth” to win elections that he in which he’s not a candidate.

According to Forbes.com, Steyer is worth $1.6 billion, which makes him the 1,190th wealthiest person in the world. He was the top national individual political donor in 2014 — at least on the books — spending almost $74 million, $46 million more than the next highest donor, former New York Mayor Michael Bloomberg. This cycle, Steyer’s near the top again, having spent $13 million so far.

“We can take on the special interests and the big corporations,” Steyer told thousands of Democrats.

However, Steyer’s spending is dwarfed by the Koch brothers — the mere mention of their name drew boos from the partisan crowd as the convention. Forbes.com has both Charles and David Koch ranked at #6 richest in the world, at $42.9 billion each.

While Steyer spends more as an individual donor, the Koch brothers reportedly have a vast network through which they spend on elections, which is difficult, if not impossible, to track. They will reportedly spend almost $1 billion on campaigns and issues this cycle.