Three coupon settlements, a corporate tax date and an FOMC meeting all land on Sept. 15

by Jonathan Mercer · September 9, 2026

Chief Markets Correspondent, US Market Current

Most of the attention on next week belongs to two events: the August consumer price report, which the Bureau of Labor Statistics has scheduled for Friday, Sept. 11 at 8:30 a.m., and the Federal Open Market Committee meeting that begins Tuesday and ends Wednesday with a fresh Summary of Economic Projections. A third event on the same calendar is getting far less airtime, and it is the one that operates on machinery rather than judgment.

On Tuesday, Sept. 15, three Treasury coupon offerings settle at once. The Treasury's tentative auction schedule shows the 3-year note auctioned Sept. 8, the 10-year note reopening auctioned Sept. 9 and the 30-year bond reopening auctioned Sept. 10, all with a Sept. 15 issue date. The Internal Revenue Service tax calendar puts the same date down for corporations to deposit the third installment of 2026 estimated tax, alongside a set of partnership and withholding-agent filings.

Those two things pull in the same direction. Settlement day is when cash actually moves from buyers to the Treasury and when dealers who took down supply have to fund the resulting inventory overnight, which they do in the repurchase agreement market. A corporate tax date pulls deposits out of the banking system and into the Treasury's account at the Fed on the same morning. Neither is unusual on its own. The question is how much give the funding market has left when they arrive together.

Fed staff put a number on that question on Aug. 26. In a FEDS Notes piece, Sriya Anbil, Alyssa Anderson, Lucy Cordes and Romina Ruprecht estimated that $100 billion of Treasury coupon issuance raises overnight repo rates by about 3.9 basis points, while $100 billion of bill issuance raises them by roughly 1.3 basis points. Coupons hit harder because they sit on dealer balance sheets and have to be financed; bills are more readily absorbed by money market funds.

The more useful finding in that note is that the relationship is not a straight line. The authors report that when Fed-supplied liquidity sits above roughly 12 percent of gross domestic product, $50 billion of coupon issuance moves repo rates by less than a basis point. Below about 10 percent of GDP, the same $50 billion is worth on the order of 10 basis points. The same supply event is nearly costless in one regime and expensive in the next, and there is no announcement when the regime changes.

The historical marker the authors reach for is September 2019, when, as they recount, a roughly $54 billion Treasury coupon settlement coincided with corporate tax outflows and the Secured Overnight Financing Rate jumped more than 280 basis points to 5.25 percent, dragging the effective federal funds rate to 2.3 percent, five basis points above the top of the target range. That episode is the reason a settlement-plus-tax-date overlap is worth flagging at all, rather than a routine calendar note.

Where does the system sit today? The Fed's H.4.1 release published Sept. 3 covers the week ended Wednesday, Sept. 2, and it prints two different things side by side: averages of daily figures for the week, and the level on the Wednesday itself. On the weekly-average basis, reserve balances with Federal Reserve Banks ran $2.895 trillion against total Reserve Bank credit of $6.687 trillion. On Wednesday itself, reserves stood at $2.929 trillion and Reserve Bank credit at $6.690 trillion. The Treasury General Account, the government's own checking account at the Fed, averaged $967.9 billion for the week and $944.4 billion on the Wednesday. Every dollar in that account is a dollar not sitting in a bank reserve balance, which is why an unusually full TGA tightens funding conditions on its own.

One line on that release is worth reading carefully, because it is routinely misquoted. The reverse repurchase agreements entry on the H.4.1 came to $365.0 billion on the weekly average and $357.7 billion on the Wednesday, but that total is overwhelmingly foreign official and international accounts. The "Others" line, which is where the domestic overnight reverse repo facility shows up, averaged $1.3 billion for the week and $525 million on Wednesday. The pool of cash that sat in that facility and quietly absorbed settlement shocks for several years is, for practical purposes, no longer there. Whatever gives next Tuesday, it will not be that.

The Fed has not been passive about this. Roberto Perli, who manages the System Open Market Account for the New York Fed, told the Money Marketeers of New York University in a March 26 speech that the FOMC judged in December 2025 that reserves had moved from abundant to merely ample, and that the Desk began reserve management purchases that month at a pace of $40 billion a month. Perli described starting early rather than waiting for the April tax season, when the Desk expected a large and rapid drain of reserves that would have required uncomfortably large purchases to offset. He also described the standing repo facility as an integral part of the rate control toolkit, used when private repo rates run above the facility's rate.

Perli's account of the run-up is worth holding next to next week's calendar. By October 2025, he said, repo reference rates had risen relative to interest on reserve balances and were printing above the effective funds rate on a sustained basis, and use of the standing repo facility became larger and more frequent as system liquidity declined. That is the pattern to watch for, and it shows up in the daily operation results before it shows up anywhere else.

The Aug. 26 note also records a force pushing the other way. The authors write that through mid-April 2026 the Desk's reserve management purchases totaled about $120 billion, which injects reserves while at the same time reducing the bill supply available to money market funds. Both effects lean the same direction on repo pricing: with fewer bills to buy, money funds have moved cash into repo lending, and the authors report that repo rates have declined several basis points as a result. That is a cushion going into next week rather than a wildcard, but it is a cushion that depends on the Desk continuing to buy.

The market absorbing all this is far larger than it was the last time it broke. In a Sept. 1 piece for the New York Fed's Teller Window, Rubi Renovato and Sophia Lansell noted that transaction volumes underlying SOFR have grown from around $1 trillion in early 2022 to $3 trillion now, and described the structure as a hub-and-spoke network with dealers as the hubs. Scale cuts both ways: more depth to absorb a settlement, but more concentrated reliance on dealer balance sheets to intermediate it.

None of this is happening against a calm rates backdrop. Treasury's own daily par yield curve data put the 10-year at 4.80 percent and the 30-year at 5.25 percent on Tuesday, Sept. 8, with the 3-month bill at 3.94 percent. TheStreet's market wrap, updated at 4:13 p.m. Eastern that day, put the S&P 500's close at 7,673.52, down 0.58 percent, the Dow at 52,786.07, down 1.18 percent, and the Nasdaq Composite at 26,421.41, down 0.32 percent. As of mid-morning Wednesday, with the session still open, Investrade's Sept. 9 mid-morning note had the S&P 500 near 7,650 and the 10-year around 4.81 percent, with Brent crude above $100 a barrel.

The practical point for anyone watching short-term rates next week is narrow. A few basis points of upward drift in repo on a settlement-and-tax day is ordinary and should not be read as stress. What would be informative is standing repo facility usage climbing, or repo prints holding above interest on reserve balances for several sessions after the settlement clears rather than snapping back. And because the Fed's communications blackout around the Sept. 15-16 meeting runs through Sept. 17, there will be no official commentary explaining any of it in real time. The operating desk's daily numbers will have to speak for themselves.