As Hillary Clinton’s campaign begins to vet possible VP picks, there’s one name on the list that is making Wall Street donors nervous: Elizabeth Warren.

The Massachusetts senator has been floated as a possible VP pick since before she announced she’d back Clinton. Warren was a coveted endorsement for the presumptive Democratic nominee, who is seeking to garner the support of Sanders’s voters. As my colleague Nora Kelly noted, Warren’s “endorsement had been anticipated as the campaign of her progressive compatriot, Bernie Sanders, winds down. It’s a loaded one: Warren has perhaps a singular capacity to united the Sanders and Clinton crowds—except for Sanders himself.”

But Warren’s anti-Wall Street position is troubling to some donors. A Politico report published on Monday relayed those concerns:

A constant theme that emerged in the interviews is that executives in the financial industry believe the first 100 days of a Clinton administration could feature potential deal making with Republicans, who are likely to maintain their majority in the House of Representatives. The dream deal for Wall Street would be a combination of targeted infrastructure spending that appeals mostly to Democrats and corporate and international tax reform that could bring Republicans along. The fear is that Warren would make such a deal more difficult.

Bankers are nervous that if Warren is Clinton’s running mate, she might move the presumptive Democratic nominee further to the left on Wall Street reform. Donors are warning that they’d pull donations to the candidate if Warren is selected, according to Politico.