Pengemarkedsforeninger defineres som kollektive investeringsinstitutter, hvis andele likviditetsmæssigt er nære substitutter for indlån, og som primært investerer i pengemarkedsinstrumenter og/eller andele i pengemarkedsforeninger og/eller i andre transferable gældsinstrumenter med en restløbetid på op til og inklusive 1 år, og/eller i bankindlån, og/eller tilstræber en afkastgrad, som ligger tæt op ad renten på pengemarkedsinstrumenter.
MMFs are defined as those collective investment undertakings (CIUs) the shares/units of which are, in terms of liquidity, close substitutes for deposits and which primarily invest in money market instruments and/or in MMF shares/units and/or in other transferable debt instruments with a residual maturity of up to and including one year, and/or in bank deposits, and/or which pursue a rate of return that approaches the interest rates of money market instruments.