“It is time for a wealth tax in America,” Ms. Warren says in the ad, which shows her speaking at a recent town hall event. “I’ve heard that there are some billionaires who don’t support this plan.”

Then the ad gets specific, identifying four billionaires and helpfully informing viewers of their estimated net worth. First is the hedge fund manager Leon G. Cooperman, who has publicly sparred with Ms. Warren (his estimated net worth: $3.2 billion).

“The vilification of billionaires makes no sense to me,” he is shown saying in the ad. “It’s bull.” Then this flashes onscreen: “Charged with insider trading.” (The Securities and Exchange Commission sued Mr. Cooperman and his firm, Omega Advisors, in 2016; he and the firm settled in 2017.)

The ad also shows footage of Joe Ricketts, the founder of TD Ameritrade; Lloyd C. Blankfein, the former chief executive of Goldman Sachs; and the venture capitalist Peter Thiel.

The ad closes with Ms. Warren asking the richest Americans to “pitch in two cents,” along with a list of social programs that could be funded with the revenue from her proposed wealth tax. Ms. Warren wants to impose an annual tax of 2 percent on net worth above $50 million, and 6 percent above $1 billion. She would use the revenue to fund proposals like universal child care, free public college and student debt cancellation, as well as to help pay for “Medicare for all.”