Sen. Elizabeth Warren of Massachusetts, one of the frontrunners in the Democratic primary, announced Tuesday that her campaign will refuse donations of over $200 from big tech companies, big banks, private equity firms and hedge funds. 

Warren said on her website that "my campaign is and will continue to be a grassroots campaign – funded by working people chipping in a few bucks here or there." 

Warren also said that she is "calling on every candidate in this race to disclose any donor or fundraiser who has a special title on their campaign, including national and regional finance committee members and bundler designations, and to disclose the dates and locations of their fundraising events and the names of every person who appears on a host committee on invitations tied to those events."

Although Warren hasn't named anyone, the statement calling for transparency could be aimed at her rivals Sen. Kamala Harris, South Bend Mayor Pete Buttigieg and former Vice-President Joe Biden, who have raised donations from wealthy donors. 

Sen. Bernie Sanders is another candidate in the race who has touted small donations. When Sanders ran for president in 2016, he boasted that his average campaign donation was $27.

Buttigieg has said that this small donations approach would not work in the general election against Trump. "We're not going to beat him with pocket change," Buttigieg has claimed, saying that Democrats need to raise as much money as possible from a "full spectrum of support." 

Warren has positioned herself as a progressive candidate who will take on Wall Street and big tech companies. She has said that her administration would break up tech giants such as Facebook and implement tougher regulations on banks.