Donor-advised funds (DAFs) are institutions with which an individual can open an account, contribute financial assets, and invest tax-free before disbursing to an eligible nonprofit. In the United States, DAF accounts are not subject to disbursement requirements; funds in DAF accounts can be reinvested indefinitely before they are disbursed, without the DAF or DAF account facing any penalties or losses of tax privileges.
On June 9, 2021, Senators Angus King (I-ME) and Chuck Grassley (R-IA) introduced the Accelerating Charitable Efforts Act, or "ACE Act". Among other provisions, the law would require newly created DAF accounts to spend the entirety of their funds within either 15 or 50 years in order for the account and its institutional sponsor to avoid tax penalties. A summary of the bill's provisions, as they currently stand, can be found here and the full text is here.