Money market funds lend $3.5tn overnight. This is what it is secured against, and who borrows it
Almost every leverage measure is a level or a schedule, including all of those on Where the Leverage Is. This one is neither. Money market funds lend to banks and dealers overnight against collateral, and that lending has to be renewed the next morning or it disappears. It is the fastest-moving liability in the system and the one that stopped in 2008 and again in March 2020.
Across 339 US money market funds holding $9.90 trillion, there is $3,494 billion of repo outstanding. Funds must name the counterparty on every one and list each piece of collateral posted against it, so both sides of the trade are public.
What they lend against is the part worth looking at. A fund lending to a dealer against Treasuries is the plumbing working normally. The orange bars are not that.
One month is a snapshot, so here is the run of them. The upper line is all repo these funds have outstanding; the lower one is the part lent against collateral that can fall in price.
Money poured into these funds and then left again: net assets peaked at $10.28 trillion in 2026-02 and repo with them, at $3,598bn in 2026-01, before both gave much of it back. The risky slice did not grow with the book. The share against non-government collateral stayed between 4.5% and 5.8% across every month, so the funds took in a fifth more money and lent it against the same mix. That is the opposite of what a deteriorating funding market looks like, and it is worth saying as plainly as the level was.
10 months, 2025-09 to 2026-06, each with a near-complete panel of around 320 funds. Months with a partial panel are dropped rather than plotted, because a half-collected month draws a cliff no money market caused.
Roughly $173 billion sits against collateral that can fall in price: corporate bonds, asset-backed paper, private-label mortgage securities and $52.4 billion against equities. Money market funds are sold as the safest thing a saver can own, and a slice of them is financing equity positions overnight. It is a small share of the total, which is the honest framing, but it is the share that would reprice first if the collateral did.
Everything above counts money. This counts counterparties. Every one of these repos names the firm on the other side of it, with an identifier, so the lending can be read as a set of relationships rather than a total. Across 365 of them, 42% of the whole book sits with five and 51% with ten. The single largest is not a dealer at all: 21% runs through a central clearing house, which concentrates the exposure on purpose and is the one case where concentration is the safety feature rather than the risk.
The part worth naming is the collateral that can fall. Of $177bn lent against it, 50% comes from five firms out of 70.
Size and exposure are different questions and the ranking answers only one. The largest lender against price-sensitive collateral has just a tenth of its own repo book there. Mizuho Securities Usa Llc is far smaller in absolute terms and runs 60% of its book against it. A reader looking only at the bars sees who is biggest; the caption on each bar is who is most committed.
One report month, 2026-07-01 to 2026-07-31. Counterparties are keyed on their legal entity identifier rather than on the name as typed, because the same dealer arrives spelled several ways and merging on text would both split one firm and merge two. One consequence is visible above: a banking group whose entities file separately appears more than once, because they are separate identifiers and separate legal counterparties. Rolled up to the group the top of this list would be more concentrated, not less. Cleared repo is shown as facing the clearing house, which is what the filing says and what the exposure actually is.
| Counterparty | Total repo | Non-government collateral | Share |
|---|---|---|---|
| Fixed Income Clearing Corp - Morgan Stanley | 733.0 | 0.0 | 0.0% |
| JP MORGAN SECURITIES LLC | 338.7 | 33.6 | 9.9% |
| CITIGROUP GLOBAL MARKETS INC. | 178.3 | 13.4 | 7.5% |
| BNP PARIBAS | 121.0 | 16.9 | 13.9% |
| WELLS FARGO SECURITIES LLC | 97.2 | 16.0 | 16.4% |
| RBC DOMINION SECURITIES INC. | 73.5 | 0.0 | 0.0% |
| ROYAL BANK OF CANADA | 72.6 | 0.0 | 0.0% |
| CREDIT AGRICOLE CORPORATE AND INVESTMENT BANK | 64.0 | 5.4 | 8.5% |
| Goldman Sachs & Co. LLC | 61.7 | 2.4 | 3.8% |
| BOFA SECURITIES, INC. | 55.2 | 6.5 | 11.7% |
| WELLS FARGO BANK, NATIONAL ASSOCIATION | 41.9 | 1.0 | 2.4% |
| BARCLAYS BANK PLC | 39.9 | 2.6 | 6.5% |
40% of this repo is cleared through a central counterparty, which mutualises the risk rather than removing it. That is the Fixed Income Clearing Corporation row, and it is the largest line in the table for that reason: it is many dealers behind one face. The rest is bilateral, one fund against one dealer, and there JP Morgan Securities is the largest at $339bn, as well as the largest lender against collateral that is not government paper. Wells Fargo Securities runs the highest proportion of it, at 16% of its book.
One report month, 2026-07-01 to 2026-07-31, 340 filings, 0 failed. Counterparties are grouped by legal entity identifier rather than by name, so the several dozen spellings of each dealer collapse correctly. Collateral values are as reported by the fund and are not haircut.
What this does not say. A stable collateral mix is not a guarantee about the next month. Repo is the fastest-moving liability in the system precisely because it can be withdrawn at a morning's notice, and every figure here is a snapshot of a market that renews itself daily.