In a development that Andrew Ross Sorkin of The New York Times believes will cause “a firestorm” in boardrooms across the country, Larry Fink, the CEO of BlackRock has sent a letter to the chief executives of the world’s largest public companies urging them to prioritize their company’s social responsibilities.

Sorkin writes that this is likely to be a watershed moment for American companies, given BlackRock’s position as one of the largest investors in the world with more than $6 trillion under management through 401(k) plans, exchange-traded funds and mutual funds.