The world’s billionaire population reached a record 2,816 in 2020, adding 346 more from the previous year, largely due to the tech boom and rising stock markets.

The billionaires’ total wealth—based on their net worth as of Jan. 31—rose 16% year-over-year to US$11.2 trillion, equating to more than the GDP of any country other than the U.S. and China, according to the Hurun Global Rich List 2020 released Wednesday.

“A...