On June 30, 2023, the Federal Reserve’s Overnight Reverse Repo (ON RRP) facility had a staggering $2.054 trillion parked overnight. By September 30, 2024, that number had collapsed to $239 billion. That’s a drainage of over $1.8 trillion in 15 months. For anyone holding cash in a prime or government money market fund (MMF), this isn’t some distant plumbing issue—it’s the mechanism that already pushed your 7-day SEC yield from 5.2% down to 4.8% before the Fed even cut rates. The transmission is mechanical, not speculative. When the RRP facility empties, the floor under short-term rates shifts, and your fund’s board has no choice but to reprice the portfolio. This article maps exactly how that drainage flows into the yield you see on your monthly statement, the 3- to 5-week lag involved, and why the next $200 billion of outflows will matter more than the last $1.5 trillion.
The ON RRP as a Rate Floor, Not a Liquidity Sink
To understand the transmission, you have to stop thinking of the Overnight Reverse Repo facility as a “liquidity drain” and start seeing it as a rate floor. When a government money market fund (G-Money Fund) lends cash to the Fed overnight, it receives a Treasury security as collateral and earns the ON RRP rate—currently 4.55% as of January 2025. That rate is an administered rate, set by the Federal Open Market Committee (FOMC), and it acts as a hard floor beneath repo markets. No G-Fund will lend to a dealer at 4.40% if it can get 4.55% risk-free from the Fed. The facility’s usage is a direct measure of how much cash is chasing too few private-market alternatives.
When usage was above $2 trillion in mid-2023, it meant money market funds had enormous sums earning that administered floor. As the Treasury Department ramped up bill issuance following the debt-ceiling resolution in June 2023, a flood of new T-bills hit the market. Funds shifted cash out of the RRP and into higher-yielding bills—often earning 5.30% or more. RRP usage plummeted. But here’s the key: the rate on the RRP didn’t change. The facility drained, but the floor remained intact. The yield on your money market fund, however, began to climb because the fund’s portfolio manager was swapping RRP at 4.55% for T-bills at 5.30%. The drainage enabled higher yields, but the mechanism was asset substitution, not a change in the administered rate.
Step-by-Step: How RRP Outflows Reach Your Fund’s 7-Day Yield
Let’s trace a concrete path from a $10 billion RRP outflow to a 3-basis-point uptick in a retail prime fund’s 7-day SEC yield. This isn’t instantaneous; it takes 3 to 5 weeks for the full effect to show up in the quoted yield. Here’s the sequence:
Week 1: The Treasury Auction and Settlement
On a Tuesday, the U.S. Treasury auctions $70 billion in 4-week bills. The auction clears at a high rate of 5.30%. Settlement occurs Thursday. Money market funds that bid directly or through dealers take delivery of the bills. To pay for them, a G-Fund redeems $10 billion from the ON RRP. The Fed’s balance sheet shows a $10 billion drop in RRP liabilities and a corresponding $10 billion increase in the Treasury General Account (TGA). The fund’s portfolio now holds a 5.30% yielding bill instead of a 4.55% RRP contract. But the fund’s 7-day yield doesn’t move yet—it’s a backward-looking average of the past week’s income.
Weeks 2–3: The Weighted Average Maturity (WAM) Effect
Money market funds report a weighted average maturity (WAM) and weighted average life (WAL) daily. Under SEC Rule 2a-7, a government fund’s WAM cannot exceed 60 days. When a fund swaps overnight RRP for a 4-week bill, its WAM extends. The portfolio’s yield-to-maturity rises because the new bill’s rate is higher than the overnight RRP rate. But the 7-day SEC yield—a standardized calculation of the fund’s net investment income per share over the prior 7 days, annualized—only gradually reflects the higher income. By the end of week 2, the RRP redemption has been earning the higher bill rate for about 10 days. The 7-day yield begins to tick up, typically by 1–2 basis points.
Weeks 4–5: Full Repricing and the Lagged Pass-Through
By week 4, the higher-yielding bill has been in the portfolio for a full 21 days. The 7-day SEC yield now fully reflects the substitution. If the fund replaced $10 billion of RRP at 4.55% with bills at 5.30%, the yield pickup is 75 basis points on that slice. For a $100 billion fund, that’s a 7.5-basis-point boost to the portfolio yield. But the 7-day SEC yield is net of expenses. A fund with a 0.15% expense ratio passes through roughly 5.5 basis points to shareholders. The observed yield moves from, say, 5.10% to 5.15%. This is the “RRP drainage dividend” that retail investors see—and it’s already priced in by the time the financial press reports on RRP balances.
Why the Last $200 Billion Matters More Than the First $1.8 Trillion
As of early 2025, the ON RRP facility holds roughly $150–$200 billion. The marginal impact of further drainage is now asymmetric. When the facility was above $500 billion, money market funds had ample room to shift cash into bills without bidding up prices. But as the RRP approaches zero, every additional dollar of Treasury issuance must compete directly with private repo and other cash investments. This is where the transmission mechanism flips: instead of RRP drainage raising MMF yields, it begins to compress short-term spreads.
Here’s the math. A prime money market fund holds commercial paper (CP) and certificates of deposit (CDs) alongside Treasuries. When the RRP facility is large, the Fed is effectively absorbing excess cash, keeping repo rates near the ON RRP floor. As the facility drains, that cash enters the private market. Dealers, now flush with cash, bid less aggressively for repo funding. The Secured Overnight Financing Rate (SOFR) drifts below the ON RRP rate. In late 2024, SOFR averaged 4.83% while the ON RRP rate was 4.80%—a 3-basis-point inversion. By January 2025, with RRP below $200 billion, SOFR was trading at 4.35%, a full 20 basis points below the ON RRP rate. Prime funds that rely on repo income see their gross yields compress. The 7-day SEC yield on the Vanguard Federal Money Market Fund (VMFXX) dropped from 5.28% in July 2024 to 4.78% by January 2025—a 50-basis-point decline that preceded any Fed rate cut.
The Regulatory Wedge: How 2a-7 Reforms Amplify the Transmission
The SEC’s 2023 money market fund reforms, which took effect in phases through October 2024, add a mechanical twist. Under the amended Rule 2a-7, institutional prime and tax-exempt funds must impose a mandatory liquidity fee when daily net redemptions exceed 5% of net assets. This fee is not discretionary—it’s a hard-coded cost that fund boards must pass through to redeeming shareholders. The mere existence of this fee structure changes how portfolio managers position their funds.
To avoid triggering the fee, institutional prime funds have shortened their WAMs and increased their allocations to overnight and weekly liquid assets. As of December 2024, the average institutional prime fund held 62% of its portfolio in assets maturing within one week, up from 48% a year earlier. This shift toward ultra-short paper means the fund’s yield is more sensitive to overnight rates—and to the RRP drainage dynamics described above. When SOFR drops 20 basis points below the ON RRP rate, a fund with 62% in overnight assets feels the compression immediately. The 7-day yield adjusts within 5 business days, not 3–5 weeks. For the retail shareholder, this means the yield on a prime fund can now fall faster than the yield on a government fund, even though prime funds historically offered a spread over government funds. That spread has collapsed from 15 basis points in mid-2024 to near zero by January 2025.
What This Means for Your Credit Card APR and Savings Account
The RRP drainage doesn’t stop at money market funds. It flows into the broader consumer finance mechanics that this publication tracks. When MMF yields decline, banks face less competition for deposits. A 50-basis-point drop in VMFXX’s yield reduces the pressure on banks to raise savings account rates. The average online savings account yield, which peaked at 4.60% in August 2024, had already slipped to 4.25% by December 2024—a 35-basis-point decline that tracked the RRP drainage and SOFR compression, not the Fed’s policy rate. This is the “deposit beta” in reverse: banks lower savings rates before the Fed cuts because their marginal funding cost has already fallen.
On the lending side, the transmission is slower but equally mechanistic. Credit card APRs are typically priced off the prime rate, which is directly tied to the Fed’s policy rate. But the spread over prime that a card issuer charges is influenced by its own funding costs. When a bank’s deposit costs fall—because MMF yields are dropping—the bank’s net interest margin widens, giving it room to tighten credit card spreads. This doesn’t happen in a week; it takes 2–3 statement cycles for a card issuer to adjust its underwriting models and repricing algorithms. A cardholder who applied for a balance-transfer card in October 2024 might have received a 3% fee and a 0% intro APR for 18 months. By January 2025, with deposit costs lower, that same issuer might offer a 0% intro APR for 21 months—a direct pass-through of the RRP-driven funding relief. For more on how rate holds affect card borrowers, see What a Rate Hold Actually Means for Credit Card Borrowers.
FAQ: RRP Drainage and Your Cash
How long does it take for RRP drainage to show up in my money market fund’s yield?
For a government fund swapping RRP for T-bills, the 7-day SEC yield typically reflects the change within 3–5 weeks. For a prime fund sensitive to SOFR compression, the pass-through is faster—often 5–10 business days—because the fund’s overnight repo positions reprice daily. The exact lag depends on the fund’s weighted average maturity (WAM) and the proportion of assets in floating-rate instruments.
Why did my prime money market fund’s yield drop even though the Fed hasn’t cut rates?
Prime funds invest in commercial paper, certificates of deposit, and repo. As the ON RRP facility drained below $200 billion, excess cash flooded the repo market, pushing SOFR down to 4.35%—20 basis points below the Fed’s administered rate. Prime funds earning SOFR on their overnight repo positions saw their income decline immediately. This compression is a direct result of RRP drainage, not a policy rate change. The Fed’s first rate cut will only accelerate a trend that’s already priced in.
Does a lower RRP balance mean my savings account yield will fall?
Yes, with a lag of roughly 4–8 weeks. When MMF yields decline, banks face less pressure to offer competitive deposit rates. The average online savings account yield fell from 4.60% in August 2024 to 4.25% by December 2024, tracking the decline in SOFR and Treasury bill rates driven by RRP drainage. Brick-and-mortar banks, which have lower deposit betas, adjust even more slowly—but the direction is the same. If the RRP facility hits zero and SOFR drops another 10–15 basis points, expect online savings yields to settle around 4.00% before any Fed action.
What happens to money market funds when the RRP facility reaches zero?
When the ON RRP facility is fully drained, the effective federal funds rate (EFFR) becomes the primary floor for short-term rates. Money market funds will then compete directly with banks for reserves, pushing repo rates potentially below the EFFR. Government funds will shift into Treasury bills and agency discount notes, compressing those yields. Prime funds will see further spread compression on CP and CDs. The 7-day SEC yield on a typical government fund could fall to 4.50% or lower, even with the Fed funds rate at 4.50%–4.75%, because of the oversupply of cash relative to high-quality short-term assets. This is the “scarcity premium” in reverse—and it’s the next chapter in the RRP drainage story.
The Next Transmission: From RRP Zero to Reserve Scarcity
The RRP facility is a buffer, not a permanent fixture. As it approaches zero, the Fed’s balance-sheet runoff—quantitative tightening (QT)—begins to directly drain bank reserves. Since June 2022, the Fed has reduced its securities holdings by roughly $2 trillion, but the RRP absorbed most of the impact. Now, with the RRP nearly empty, further QT will reduce reserve balances dollar-for-dollar. When reserves fall below roughly $3 trillion—the “ample reserves” threshold estimated by the New York Fed—the federal funds rate can become volatile. This is the point where the transmission mechanism inverts again: instead of MMF yields falling, they could spike temporarily as banks bid aggressively for overnight funding.
For the consumer, this means a period of unpredictable short-term rates. A money market fund’s 7-day yield might swing 10–15 basis points in a week. A credit card issuer might widen its spread over prime to compensate for funding uncertainty. The time lag from reserve scarcity to your wallet is short—often 2–4 weeks—because it operates through the overnight funding markets that reprice daily. This is the mechanistic reality of the post-RRP world, and it’s already showing up in the data.
