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Why Overnight Repos Provide Flexible Short-Term Funding

Article Quant Q&A · Author: Mustard Tiger

Summary

The document explains why market participants use overnight repurchase agreements instead of locking in financing for a longer period. A dealer or investor holding Treasury securities can borrow cash against them, using the repo to finance the position. Overnight funding can be renewed each day, allowing the borrower to adjust the amount or unwind financing as securities are sold and settlement proceeds arrive. This flexibility matters when the holder’s investment horizon is uncertain.

The answers also describe the economics on both sides of the transaction. Borrowers may prefer overnight rates when they are below longer-term funding costs, while money market funds value short maturities because they offer investors daily liquidity. Repos can also redistribute cash among institutions with daily funding surpluses or deficits, using collateral to limit credit exposure. These motives complement one another, but the document does not claim that overnight funding is always cheaper or risk-free. Rates and availability can change, and a borrower relying on daily renewal remains exposed to the terms and conditions of future funding.

Key ideas

  • Overnight repos finance securities holdings with cash borrowed against collateral.
  • Daily renewal lets borrowers adjust funding as positions and settlement needs change.
  • Borrowers may favor overnight financing when its rate is below the cost of longer-term funding.
  • Money market funds may use short repos to support daily liquidity for their investors.
  • Repos help redistribute cash between institutions while collateral limits credit exposure.

Tags

Full text
# Practical purpose of overnight repos


# Practical purpose of overnight repos












I know this might not be a very quantitative question, but I figure this is the most relevant place to ask this.

Over that last few days, there has been a lot of news from the repo market, for example, https://www.bloomberg.com/news/articles/2019-09-17/with-repo-market-still-on-edge-fed-preps-second-blast-of-cash

Approximately half of the repo market is attributed to overnight repurchase agreements. What is the point of entering a repo agreement for such a short term? I have been able to find a lot of material with examples of two parties entering the agreement and explanations of how they work, but what is the motivation?

If I put up 100 million worth of treasury bills and in return, get cash and enter an agreement that I have to repurchase those bills the next day, what is the point of that cash? What can I do with that money in such a short time? Is it simply for some regulatory/filing purposes to show that you have cash on hand?

## Answer by kdragger (score 4)

https://quant.stackexchange.com/a/51213

The reason that repos are often overnight is because it corresponds with the settlement and funding processes, and people want maximum flexibility. Note further that most overnight RPs are rolled over (renewed) each day with the amounts potentially changing.

To use your example: I buy 100M of 2 year notes and need to fund it. Great. That works. Why not fund for 2 years? Because I'm not going to hold it that long and, tbh, I don't know how long I'm going to hold it. But I do know that normal settlement occurs next day in USTs. So if I sell $100M (or $50M) of my position today, I can unwind my financing tomorrow.

Why don't I fund it for 2 yrs? Because I want flexibility and there is often carry involved. Usually the overnight rate is less than the 2 year rate. Generally that is what leveraged money is after: I buy a 2 year note at 2% and fund it overnight at 1.55%. Unsurprisingly, the 2 year RP rate will probably closely match the 2 yr note yield (this would not generally be true for assets farther out the risk spectrum).

## Answer by dm63 (score 4)

https://quant.stackexchange.com/a/51240

One important reason why repos are often short term is that the banks obtain the other side of the market from money market funds. These investors want to make a cash deposit secured by high quality collateral (i.e. a reverse repo). However it must be short term because they are offering daily liquidity to their investors at a price equal to par. If they were to invest in (say) 6month repo, they would be stuck if a lot of folks withdrew their money from the fund.

## Answer by VanillaCall (score 2)

https://quant.stackexchange.com/a/48759

You have positions that you need to finance via overnight repo. You secure financing by simultaneously entering into repo transaction with a bank to secure the cash to purchase the Treasury security, then providing this security to the bank as collateral.

in other words, this is a form of collateral lending similar to getting a mortgage on a house. You don't have millions of dollars sitting around so you obtain a loan to buy the property. If you fail to make repayment on your loan, the bank seizes your house.

## Answer by demully (score 2)

https://quant.stackexchange.com/a/51254

Ok, think about it this way... every time any bank's customer enters any transaction with someone else, who is the customer of a different bank, there is an inter-bank transfer.

Each bank's balance at the central bank at the close of business will be different. But the aggregate will be no different; just the composition/mix. Cash can move around within the system; but can't (or struggles to) ever enter or exit the system. You buy gold; your cash just goes to the seller's account...

This variability in the flow of transactions doesn't change the cash circulating in the system; but it does alter its distribution, who ends up with the surpluses and who the deficits on any day to the next. Repos simply allow banks to net these off in a manner free from credit risk (given the colllateral). One bank will have excess cash, and not so keen earning below-repo with excess reserves. Another will have the opposite, and not so keen covering this direct with the CB. Repos just net off these floating fluctuation, without credit risk.

As such, they're far from elegant; just less inelegant than the alternatives.

Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.