Plank is worth $3 billion, according to the financial magazine, up from $1.7 billion a year ago. He has climbed from No. 345 to No. 327 to No. 190 over the past three years.
Bisciotti, whose wealth comes both from the Ravens and the staffing firm Allegis Group, is worth $2.6 billion, ranking No. 235 on the list. His wealth also grew over the past year, from $2.1 billion and No. 260 on last year's list.
A strong stock market has helped the top tier of America's wealthy to get even richer, according to Forbes. A net worth of at least $1.55 billion was required to make this year's list, the most since Forbes began tracking the data in 1982.
Facebook CEO Mark Zuckerberg gained the most wealth over the past year, adding $15 billion to reach a net worth of $34 billion because of the rising price of the social networking company's stock.
Rising stock also buoyed Plank, who owned 18.5 percent of Under Armour shares as of March, according to Securities and Exchange Commission filings. The sportswear company's stock has climbed from about $39 per share a year ago to hover around $70 in recent months.
Bisciotti's gains can be attributed to the rising value of the Ravens franchise — at least, as of August. At that time, the team was worth $1.5 billion, according to Forbes, up 22 percent over the previous year. But Bisciotti's profile among the Forbes 400 notes that he "got caught up in a mess" over former Ravens' running back Ray Rice's abuse of his wife and adds that "questions about how Bisciotti handled the controversy continue."