Early Fund-Raising Divides the Democratic Field Into Haves and Have-Nots

“I’m excited that campaigns finally understand the value and return on investment” of digital advertising, said Tara McGowan, a Democratic digital strategist unaligned in the primary. “That is a long time coming.”

President Trump’s campaign and his joint fund-raising committees with the Republican National Committee continued to outspend Democrats online, particularly on Facebook, where they have spent $4 million this year, ad records show.

Mr. Trump continues to direct campaign spending toward businesses that he is linked to, a practice that has drawn criticism. Among his $378,000 in such spending was $215,000 for space at his Mar-a-Lago resort in March and $112,000 in rent to Trump Tower.

The fund-raising reports also offer new details on the donors whom the candidates are raising money from.

Mr. Sanders overwhelmingly received money from donors who gave less than $200 (84 percent of his total money raised), as did Ms. Warren (70 percent). Both have sworn off attending the kind of closed-door fund-raising events that have long been a staple of the presidential circuit. Ms. Gillibrand, Senator Cory Booker of New Jersey and former Gov. John Hickenlooper of Colorado were most dependent on larger contributors, with small donors contributing less than 20 percent of their money raised.

Ms. Harris led the field with $7.6 million collected from contributions over $200, eclipsing her nearest competitor in that category by more than $3.3 million. She raised approximately $3.9 million from donors who gave her between $2,700, the maximum contribution in the last election cycle, and $2,800, the new legal limit.

Mr. Buttigieg raised $2.5 million from larger donors in the first quarter. Several connected fund-raisers, including Orin Kramer, a longtime fund-raising bundler and hedge fund founder, have recently signed on to help Mr. Buttigieg.