Regulation (EU) 2017/1131 establishes a Union-wide prudential, governance and transparency regime for money market funds (MMFs). It defines MMF types (VNAV, public-debt CNAV and LVNAV), prescribes mandatory authorisation, restricts eligible assets and activities, and mandates internal credit-quality assessment, stress testing and know-your-customer liquidity procedures. Use of the MMF designation is prohibited unless authorised.

Portfolio controls set weighted-average maturity/life and liquidity buffers, limit exposures, cap securitisation and repo activity, and forbid external sponsor support. Valuation is by mark-to-market, with mark-to-model or amortised-cost limited for specified fund types. Managers must report regularly to competent authorities and ESMA; supervisors have investigatory and sanctioning powers. The Commission will review the regime by 21 July 2022, including a possible EU public-debt quota.