Iowa is upon us and so come the big-money donors making last-minute efforts to ensure their candidate succeeds. In the Democratic race, Hillary Clinton continues to be powered, in part, by millionaires and billionaires, while her competitor Bernie Sanders is pulling in small donations.

The latest news from the Clinton super PACs: Billionaire George Soros contributed $6 million last month, according to the latest filings for the committee, the Hill reported Sunday. Priorities USA Action, which is Clinton’s largest campaign super PAC, has raised $25.3 million over the last six months and $50 million in total. Independent groups American Bridge and Correct the Record have garnered $6 million in total, CNN reports.

Vermont Sen. Bernie Sanders campaign pulled in $20 million in January from more than 770,000 donors. About 1.3 percent of Sanders’ donors have reached the donation limit of $2,700 imposed by the Federal Election Commission, the Wall Street Journal reported. “Working Americans chipping in a few dollars each month are not only challenging but beating the greatest fundraising machine ever assembled,” Jeff Weaver, campaign manager for Sanders, said in a statement.

Sanders does not have super PACs funding his campaign and has frequently spoken against the current state of campaign financing:

I am proud to tell you that I am the only candidate on the Democratic side that does not have a super PAC. — Bernie Sanders (@BernieSanders) January 31, 2016

I do not represent corporate America and I don’t want their money. — Bernie Sanders (@BernieSanders) January 31, 2016

We need to create a culture which cannot just be based on the worship of money. — Bernie Sanders (@BernieSanders) January 31, 2016

It is absurd that one family (the Waltons of @Walmart) has more wealth than the bottom 130 million Americans. pic.twitter.com/qohh31E5iq — Bernie Sanders (@BernieSanders) February 1, 2016

Sanders also has spoken against Clinton’s and others’ financial support that is driven by Wall Street. “I don’t take money from big banks,” Sanders said at the last Democratic debate in Charleston, South Carolina, on Jan. 17. “I don’t get personal speaking fees from Goldman Sachs.”

Instead, Sanders is fueling his campaign from direct donations from voters. He has received big endorsements, including from Democracy for America and Communications Workers of America.