A facility where money market funds park their cash overnight at the Federal Reserve for interest, which takes that cash out of the market cycle. A rising balance means idle cash. A falling balance means it is returning in search of yield.
What these agreements are
Reverse Repo (RRP · Reverse Repo) is a Federal Reserve facility where money market funds deposit surplus cash night after night for guaranteed interest. Cash leaves the financial system to sleep in the safest bed on the planet, idle and out of the chase for assets.
Why it is the reserve liquidity tank
Its balance measures surplus cash that found no better use. When it swells (it reached trillions at the peak of the glut), liquidity exceeds what the market needs. When it drains, its cash returns to the system. It can fund Treasury issuance without pulling a dollar from asset markets. That safety valve let a full quantitative tightening pass with relatively little damage.
Reading it at the margin
The middle levels are plumbing details. The limits are the signal: its drain toward zero means the cushion is gone. From there on, every liquidity drain (issuance, balance-sheet reduction) is paid straight out of market cash, so assets become more sensitive to each wave of government supply.
Hypothetical example
A full year of heavy Treasury issuance passes while stocks rise: the absorber was RRP draining from $2,200 billion toward the hundreds. The cushion paid the bill. As it nears empty the equation flips: the same later issuance now creates noticeable pressure. The event didn't change; the cushion did.
Common mistake
Projecting the past onto a different phase: “issuance didn't hurt the market last year” is true because the cushion was thick. Applying that to a phase where the cushion has run dry is a structural error, not an estimation error.
Where to see it on the platform
The Net Liquidity indicator tracks its daily balance among its components and flags when it nears depletion thresholds.
