Senator Elizabeth Warren – last seen hurling attacks on Michael Bloomberg – now has a new target: Larry Fink of BlackRock.

The Democratic candidate is pushing for the BlackRock chief to do more in his firm’s pledge to address climate change. In a letter released today, Warren asked Fink to support her latest climate plan – the Climate Risk Disclosure Act. This bill would require all companies to reveal their business risks tied to climate change.

“If BlackRock plans to live up to the commitments you made, we hope that you will go further by endorsing the reforms laid out in the Climate Risk Disclosure Act, and require companies in which you invest to issue public disclosures consistent with its requirements,” she wrote.

Warren argues that government metrics provide one of the clearest ways to track sustainability pledges by companies.

Senator Elizabeth Warren on BlackRock

In addition to seeking support for her bill, Warren is also asking Fink to provide more clarity on how he plans to make sustainability the “new standard for investing.” The letter also asks for more detail on the “concrete steps” that BlackRock will take to ensure it meets its commitments. Finally, the Senator is looking for more clarity into the exchange-traded funds that will center on ESG.

Last month, Fink announced his firm will divest from assets with a negative impact on the environment, such as coal.

Fink famously said that he expects that ESG and climate change will lead to “a fundamental reshaping of finance.”

The company also joined Climate Action, an investor coalition that aims to reduce greenhouse gas output.

“Your letters to CEOs and investors suggest that you understand the extent of the effects that climate change will have on the economy and that BlackRock, as a fiduciary to your clients needs to understand climate risks across the investments it makes,” wrote Warren, along with several other members of the Democratic leadership.