Billionaire Tom Steyer refused to say whether he would use his own fortune to fund a potential 2020 bid for the Democratic presidential nomination ahead of a scheduled announcement about his political plans.

“If you look at look at what I’ve done over the last six years working full-time in grassroots politics, I’ve spent all of my money pushing power down to the people,” he told reporters after an event in Iowa, site of the first nominating contest more than a year from now. “I understand that there is a huge issue with money in politics.”

Steyer, 61, wouldn’t give any hints whether his announcement Wednesday afternoon would be about his intentions in the presidential race.

In her first trip to Iowa as a likely presidential candidate, Sen. Elizabeth Warren of Massachusetts repeatedly criticized the idea that wealthy presidential hopefuls might use their personal fortunes to fund campaigns, a notion she said Democrats should find offensive.

“Campaigns should not be for sale,” she said at a stop in western Iowa last weekend. “As Democrats in a Democratic primary, we ought to be building grassroots support. We ought to be building a movement, not having billionaires buy these campaigns, whether we’re talking about super PACs or self-funders.”

Although Warren didn’t mention them by name, Steyer and fellow billionaire Michael Bloomberg have indicated they’re considering joining the Democratic fray and have the resources to finance their own campaigns if they wanted to do so.

Steyer, a former hedge fund manager, has spent millions of dollars on a campaign calling for President Donald Trump’s impeachment.

Bloomberg, a former New York City mayor who’s the founder and majority owner of Bloomberg LP, the parent company of Bloomberg News, made a trip to Iowa in early December to showcase the climate change issue.

The two men are among more than two dozen Democrats believed to be seriously contemplating bids for the party’s 2020 nomination, although none, with the possible exception of former Vice President Joe Biden, are obvious front-runners.