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CVA for Daily Collateralized Swaps: Residual Exposure and Margin Period Risk

Article Quant Q&A · Author: Randor

Summary

The discussion explains why credit valuation adjustment can remain relevant for a swap with daily collateral. Collateral terms may leave residual exposure through thresholds, minimum transfer amounts, and other imperfections. If a counterparty defaults, collateral posting may cease while the swap’s market value continues to move, creating exposure over the margin period of risk. Initial margin is described as covering a selected quantile of market value changes over that period, whereas potential future exposure concerns a quantile of positive credit exposure.

One answer argues that the adjustment may be small for an isolated swap and a short period, but that it can accumulate for a large, long-dated, one-sided book or under adverse dependence between market rates and counterparty credit. Another answer similarly emphasizes examining conservative assumptions for the period and correlation. These are contextual judgments, not a general quantitative result: the thread gives no full calculation, and its participants disagree about how CVA, potential future exposure, and initial margin relate. Portfolio size, collateral terms, replacement time, and wrong-way risk affect the assessment.

Key ideas

  • Daily collateral reduces counterparty exposure but does not eliminate it when collateral terms are imperfect.
  • Exposure can grow after default while collateral is no longer being posted and the swap value moves.
  • Initial margin is framed as covering market value changes over the margin period of risk, while potential future exposure measures credit exposure quantiles.
  • CVA materiality depends on portfolio direction and size, replacement time, collateral terms, and market-credit dependence.
  • The thread offers estimates and opinions rather than a universal rule for when CVA is negligible.

Tags

Full text
# cva for a collateralised swap


# cva for a collateralised swap












For a swap thats fully collateralised once a day, i suppose that the cva measures risk only for the intraday chance of counterparty default? Surely thats tiny enough to be neglible, or am i missing something?

## Answer by byouness (score 2)

https://quant.stackexchange.com/a/39526

Collateral imperfections: the CVA cover the expected exposure in the event that the counterparty defaults. When the trade is collateralized and subject to variation margin. This exposure will come only from the imperfection of the collateral. Because posting and receiving collateral actually has a cost, usually the collateral agreement will be a threshold amount (bellow which no collateral is posted / received), and a minimum transfer amount.

The Margin period of risk: Also, when computing the CVA, you are concerned with the case where the counterparty defaults, and in this case before the default, the counterparty would usually stop posting collateral for a given period (called margin period of risk), usually around 10 days. In this period, the value of the swap can move with the market and diverge from the collateral balance.

The initial margin: The IM is supposed to cover these market values moves during the MPOR, it's a quantile like PFE, but it not the same as PFE is a quantile of the credit exposure = max(MV(t), 0) whereas the initial margin is a quantile of the market value variation over the margin period of risk = MV(t + MPOR) - MV(t).

## Answer by Mehness (score 0)

https://quant.stackexchange.com/a/31527

I would say it is negligible, the only times have ever had to compute that on standalone ISDAs (with just one albeit large swap) it's really honestly been very small perhaps a few tens of k for a 500mm swap over 15 years from distant memory, even if you say for example that your period of risk is greater than a day (let's say you have a massive swap, a major deriv cprty defaults, whole market is same way around so you can't replace your market risk hedge as quickly as you'd like - inconceivable in vanilla swaps but bear in mind regulatory hedge replacement windows typically assume 7 days or similar).

This is even in the context of wrong way credit rates correlation - if you model credit intensity and rates as correlated brownians you just aren't going to get a material one day move. As a caveat I would say however if you have a large long dated swap book that is very one way vs a counterparty (let's say you are receiving fixed and assume low rates <-> wide credit), then obviously it will add up. So as in many problems, it's worth looking at with conservative assumptions on period of risk and correlation, to allow you decide if you can afford to ignore it on your portfolio. Regulators as mentioned do demand a marghin period of risk, but unless am wrong for certain banks, this does not generally make it into economic CVA calculations and hedging decisions.

## Answer by Randor (score -1)

https://quant.stackexchange.com/a/31530

i think that cva is meant to cover Expected credit losses and PFE x% covers Unexpected credit losses and so gap risk would be more covered by PFE

i think initial margin for ccp cleared trades is more like a charge for PFE than for cva

So, i still dont really fully get where the demand for cva is coming from

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.