money market funds yield close to the risk free rate (think of FED funds rate in the US, or ECB deposit rate in the EU), while offering less risk due to shorter maturity
essentially, you provide a collateral (highly liquid - usually sovereign debt) and get a loan against it
record $7 trillion USD in money market funds (mmf)
this risk-averse liquidity is bound to flow into into other financial assets at some point
mmf consists of short-term collateralized loans - credit that is NOT captured by M2
last two outflows coincided with bitcoin bullrun