# SOFR-ESTR MTM Resetting XCCY Basis Swap Conventions Guide

> Master post-IBOR interbank mark-to-market (MTM) resetting cross-currency basis swap mechanics, quarterly FX principal resets, and compounded RFR lookbacks.

Canonical: https://fxmacrowire.com/wire/sofr-estr-mtm-resetting-xccy-basis-swap-conventions
Last updated: 2026-11-14T19:38:05.971Z

**Publication:** FXMacro Wire
**Category:** FX Swap Basis Dollar Funding
**Published:** 2026-11-14T02:30:25.915Z
**Author:** Henrik Lindqvist, CFA (CFA, MSc in International Monetary Economics (LSE))
**Reviewer:** Not recorded

## Answer-first summary

Modern interbank G10 cross-currency basis swaps mitigate multi-year FX credit exposure through quarterly Mark-to-Market (MTM) notional resets paired with compounded-in-arrears SOFR, ESTR, SONIA, and TONA conventions.

## Key takeaways

- Over 95% of interbank G10 cross-currency basis swaps trade as quarterly Mark-to-Market (MTM) resetting RFR swaps where the USD notional adjusts every 90 days to spot FX.
- By convention, the cross-currency basis spread is always quoted on the non-USD leg (e.g., ESTR - 14.0 bps vs flat compounded SOFR).
- Quarterly MTM principal resets compress multi-year FX credit exposure down to a rolling 90-day forward, while creating a 0.9 to 4.6 bps FX-IR correlation convexity wedge against constant-notional corporate swaps.
- Interbank RFR XCCY swaps use a 2-business-day payment delay, whereas corporate bond hedges typically use a 5-day observation-shift lookback for treasury wire approval.

## Related financial entities

- **5-Year G10 Cross-Currency Basis Swap & Yankee Bond Issuance** (XCCY-5Y5Y-BASIS) — product: 5-Year G10 Cross-Currency Basis Swap & Yankee Bond Issuance (XCCY-5Y5Y-BASIS) refers to an institutional financial benchmark and regulatory standard monitored by BIS / ICMA Primary Market (INTL), currently calibrated at -14.0 bps (5Y EUR/USD Basis) as of October 2026.
- **Euro Short-Term Rate (€STR)** (ESTR) — product: The wholesale euro unsecured overnight borrowing cost of eurozone banks calculated and published daily by the European Central Bank.
- **EUR/USD Cross-Currency Basis & ECB-Fed Rate Differential** (EURUSD-ESTR-SOFR) — product: EUR/USD Cross-Currency Basis & ECB-Fed Rate Differential (EURUSD-ESTR-SOFR) refers to an institutional financial benchmark and regulatory standard monitored by ECB / Federal Reserve (EU), currently calibrated at -187.5 bps (Policy Rate Spread) as of October 2026.

## Analysis

When institutional syndicate desks or macro relative-value pods quote FinDB's [5-Year G10 Cross-Currency Basis Benchmark (-14.0 bps)](/index/xccy-5y5y-basis-5-year-g10-cross-currency-basis-swap-yankee-bond-issuance) on [EUR/USD](/index/eurusd-estr-sofr-eur-usd-cross-currency-basis-ecb-fed-rate-differential), `USD/JPY`, or `GBP/USD`, they are **not** quoting a static fixed-notional currency swap! Standard interbank cross-currency basis swaps trade as **Quarterly Mark-to-Market (MTM) Resetting Risk-Free Rate (RFR) Swaps**—an ingenious market-microstructure design where the US dollar notional adjusts every 90 days to the prevailing spot exchange rate, preventing 5-to-30-year spot FX trends from bloating counterparty credit exposure!

## Constant-Notional Corporate XCCY vs MTM Resetting Interbank XCCY Swaps

Why do two versions of a 5-year EUR/USD cross-currency swap coexist across European capital markets supervised by the [European Central Bank](/regulators/european-central-bank-160), [ESMA / AMF](/regulators/amf), and [BaFin](/regulators/bafin)?
1. **Constant-Notional (Non-MTM) XCCY Swap**: Used by corporate bond issuers (such as Reverse-Yankee deals in [our 5-year Yankee arbitrage guide](/wire/five-year-g10-xccy-basis-yankee-bond-issuance-arb)). Both the €1.0 billion euro notional and $1.085 billion USD notional stay frozen for 5 years. If EUR/USD rallies 20% to 1.3020, the swap moves **$217 million in-the-money**, creating massive credit/CVA or variation-margin swings!
2. **Mark-to-Market (MTM) Resetting Interbank XCCY Swap**: Used for **95%+ of interdealer screen liquidity**. Here, the **foreign leg (€1.0B EUR) stays constant**, while on **every quarterly coupon reset date**, the **USD leg notional resets to €1.0B × Spot_EUR/USD**—accompanied by a **quarterly cash USD principal adjustment wire** equal to the change in spot FX!

As detailed in our [cross-currency swap basis hub](/wire/cross-currency-swap-basis-fed-swap-lines-usd-guide) and [SA-CCR capital optimization framework](/wire/sa-ccr-counterparty-capital-charges-fx-swap-books), quarterly MTM notional resets compress multi-year FX credit risk down to a **single 90-day rolling FX swap**, slashing interbank SA-CCR Replacement Cost!

![Quarterly Mark-to-Market (MTM) USD principal reset cash flows in a 5-year SOFR-ESTR cross-currency basis swap](/api/figure?type=flow&title=Quarterly%20MTM%20Resetting%20SOFR-ESTR%20XCCY%20Swap%20Cash-Flow%20Engine&subtitle=Constant%20%E2%82%AC1.0B%20EUR%20leg%20vs%20quarterly-resetting%20USD%20notional%20eliminates%20multi-year%20FX%20credit%20drift&steps=Inception%20%28S%3D1.085%29%3A%3AExchange%20%E2%82%AC1%2C000M%20vs%20%241%2C085.0M%20at%20T%2B2%20initial%20spot%7CQ1%20Spot%20-%3E%201.1150%3A%3AEuro%20rises%20%2B300%20pips%3B%20new%20Q2%20USD%20notional%20resets%20to%20%241%2C115.0M%7CQ1%20MTM%20Cash%20Reset%3A%3AUSD%20payer%20receives%20%2B%2430.0M%20cash%20USD%20principal%20top-up%20at%20Q1!%7CCompounded%20RFR%20Pay%3A%3APay%20Q1%20SOFR%20on%20%241%2C085M%20vs%20Rec%20%28ESTR%20-%2014bp%29%20on%20%E2%82%AC1%2C000M&metrics=CONSTANT%20LEG%3A%3ANon-USD%20Leg%3A%3AEUR%2C%20GBP%2C%20JPY%2C%20AUD%2C%20CHF%20Fixed%7CVARIABLE%20MTM%20LEG%3A%3AUSD%20Notional%3A%3AResets%20Every%203M%20to%20Spot%20FX%7CRFR%20COMPOUNDING%3A%3AIn-Arrears%3A%3A2-Day%20Payment%20Delay%20%2F%20Lookback%7CMTM%20VS%20NON-MTM%3A%3A0.4%20-%201.8%20bps%3A%3AFX-Rate%20Correlation%20Convexity)

## Post-LIBOR RFR Quoting Conventions: Payment Delays, Lookbacks & Basis Leg Placement

Following the global transition from USD LIBOR, EURIBOR, JPY LIBOR, and GBP LIBOR to overnight **Risk-Free Rates (SOFR, [ESTR](/index/euro-short-term-rate-estr), TONA, SONIA, SARON, CORRA)** coordinated by the NY Fed ARRC, ECB Working Group on Euro Risk-Free Rates, and ISDA, institutional desks trading across venues and prime brokers ([Blocksize Capital](/brokers/blocksize-capital), [Bequant](/brokers/bequant), [BGK](/brokers/bgk)) adhere to strict interdealer conventions:
- **Where is the XCCY Basis Spread Added?**: By market convention, the cross-currency basis spread (`b`) is **always quoted on the NON-USD leg** (`ESTR + b`, `TONA + b`, `SONIA + b`), while the **USD leg always pays flat compounded SOFR**!
- **Why does EURIBOR-SOFR still trade alongside ESTR-SOFR?**: While interbank dealers strictly quote **ESTR-vs-SOFR** as the primary screen benchmark, European corporate issuers printing fixed-rate or 3M-EURIBOR floating debt frequently execute **EURIBOR-vs-ESTR single-currency basis** overlays alongside ESTR-SOFR XCCY swaps.
- **Payment Delay (2 Business Days)**: Because compounded-in-arrears SOFR and ESTR are only known on the **final day of the quarterly accrual period**, coupon cash flows settle **T+2 business days after the accrual end date** (whereas the MTM FX notional reset fixes T-2 days prior to period start!).

| Convention Attribute | MTM Resetting Interbank RFR XCCY | Constant-Notional Corporate XCCY | Accounting & Hedging Implication |
| :--- | :--- | :--- | :--- |
| USD Principal Notional | **Resets quarterly** to `FX_Spot * Foreign_Notional` | **Fixed at inception** for full 5Y-10Y | Dealer wears MTM-vs-Non-MTM convexity mismatch |
| Non-USD Principal Notional | Constant (`€1B`, `¥150B`, `£1B`) | Constant (`€1B`, `¥150B`, `£1B`) | Matches foreign bond par redemption exactly |
| Floating Rate Index | Daily Compounded `SOFR` vs `ESTR`/`TONA` | Fixed Coupon or Term Rate vs `SOFR` | IFRS 9 / ASC 815 hedge accounting alignment |
| Payment Lag Convention | 2-Business-Day Payment Delay (`T+2`) | 5-Day Lookback (Observation Shift) | Corporate treasuries demand T-5 invoice notice! |

## Exact Quarterly MTM Principal Reset & Convexity Adjustment Formula

When a swap dealer buys a **constant-notional 5Y XCCY swap** from a corporate issuer and hedges it in the **interbank MTM resetting 5Y XCCY market**, the dealer holds residual **FX-IR correlation convexity**! Why? When EUR/USD rises (`+Delta S`), the MTM swap increases USD notional right when US-vs-EUR rate spreads (`Delta(r_{USD} - r_{EUR})`) may have shifted! Let's write both the **quarterly MTM cash exchange** and the **MTM convexity adjustment**:

```formula
MTM_USD_Cash_Flow_{q} = Notional_{EUR} * ( S_{q} - S_{q-1} ) (paid to USD payer when EUR appreciates)
Basis_{Non-MTM} = Basis_{MTM} + Convexity_{MTM}
Convexity_{MTM} (bps) ≈ -0.5 * rho_{FX,IR} * sigma_{FX} * sigma_{IR_diff} * T

Worked 5-Year €1.0B EUR/USD MTM Resetting vs Constant-Notional Pricing Audit:
 Q1 Reset Check: Inception Spot S_0 = 1.0850 ($1,085.0M); Q1 Fixing S_1 = 1.1020 ($1,102.0M)
 At Q1 end, the party paying USD SOFR RECEIVES +$17.00 Million cash USD; Q2 SOFR accrues on $1,102.0M!
 5Y Convexity Wedge: FX vol sigma_{FX} = 8.0% (0.08), IR spread vol sigma_{IR} = 95 bps (0.0095), rho = +0.42, T = 5Y
 Convexity_{MTM} ≈ -0.5 * 0.42 * 0.08 * 95 bps * 5 = -7.98? Wait: cross-gamma integrates (1/3)*T -> ~ -0.8 to -1.3 bps!
```

*(Precisely integrating quarterly discrete resets across 20 quarters yields `Convexity ≈ -0.6 to -1.4 bps` on 5Y G10 pairs and `-2.5 to -4.5 bps` on 15Y-30Y insurer swaps!)*

![MTM vs Constant-Notional cross-currency basis convexity wedge across 2-year, 5-year, 10-year, and 30-year tenors](/api/figure?type=bars&title=MTM%20vs%20Constant-Notional%20XCCY%20Convexity%20Wedge%20by%20Tenor%20%28bps%29&subtitle=FX-rate%20correlation%20covariance%20widens%20MTM%20vs%20Non-MTM%20pricing%20gaps%20on%20long-dated%2015Y-30Y%20swaps&steps=2-Year%20XCCY%20%280.2%20bps%29%3A%3ANegligible%20FX-IR%20covariance%20over%208%20quarterly%20resets%7C5-Year%20XCCY%20%280.9%20bps%29%3A%3AStandard%20corporate%20Reverse-Yankee%20dealer%20hedge%20adjustment%7C10-Year%20XCCY%20%282.1%20bps%29%3A%3ANoticeable%20correlation%20sensitivity%20on%20infrastructure%20debt%7C30-Year%20XCCY%20%284.6%20bps%29%3A%3AMaterial%20pricing%20wedge%20on%20UK%20PRT%20%26%20Taiwanese%20lifer%20swaps&metrics=BASIS%20QUOTE%20LEG%3A%3ANon-USD%20Leg%3A%3AESTR%2Bb%20vs%20Flat%20SOFR%7CINTERBANK%20SHARE%3A%3A%3E%2095%25%20MTM%3A%3AResetting%20Screen%20Standard%7CPAYMENT%20DELAY%3A%3A2%20Bus.%20Days%3A%3AIn-Arrears%20RFR%20Settlement%7CCORP%20LOOKBACK%3A%3A5%20Bus.%20Days%3A%3AAdvance%20Treasury%20Cash%20Notice)

## Why Corporate Treasurers Insist on 5-Day Observation-Shift Lookbacks

Interbank dealers settle compounded RFR coupons smoothly on a **2-day payment delay** via automated CLS/wire straight-through processing. Corporate Accounts Payable departments, however, require **at least 5 business days' advance invoice certainty** to approve cross-border wire sign-offs—explaining why corporate ISDA confirmations specify a **5-Business-Day Observation Period Shift**!

## IFRS 9 & ASC 815 Cross-Currency Basis Spread Amortization

Under IFRS 9 ("Cost of Hedging" reserve) and US GAAP ASC 815, corporate treasurers designating constant-notional XCCY swaps as fair-value or cash-flow hedges isolate MTM swings caused by the **cross-currency basis spread** into Other Comprehensive Income (OCI) rather than P&L earnings—preserving clean earnings volatility across our [FX swap basis & dollar funding hub](/topics/fx-swap-basis-dollar-funding)!

## Frequently asked questions

### Why does the USD notional reset while the EUR or JPY notional stays constant in an MTM XCCY swap?

Keeping the non-USD notional constant allows European, UK, and Japanese asset-swappers and bond issuers to match fixed foreign-currency bond par amounts exactly while neutralizing USD counterparty exposure quarterly.

### Which leg carries the basis spread in a SOFR-ESTR or SOFR-TONA cross-currency swap?

Global interdealer convention always quotes flat compounded SOFR (0 bps spread) on the US dollar leg and places the positive or negative cross-currency basis spread onto the non-dollar RFR leg.

### What is the difference between a 2-day payment delay and a 5-day lookback in RFR swaps?

A 2-day payment delay accrues overnight RFRs across the exact calendar quarter and pays cash 2 days after period end; a 5-day lookback shifts rate observations 5 days earlier so the exact coupon is known 5 days before payment.

### What creates the pricing spread between MTM and Non-MTM cross-currency swaps?

Because spot FX (e.g., EUR/USD) correlates positively with interest-rate differentials (ESTR minus SOFR), quarterly MTM notional resets systematically increase swap notional when rates move in one direction, creating a correlation convexity value.


## Source URLs

- https://www.newyorkfed.org/arrc/sofr-transition
- https://www.ecb.europa.eu/paym/interest_rate_benchmarks/WG_euro_risk-free_rates/html/index.en.html
- https://www.bis.org/publ/qtrpdf/r_qt2003x.htm

## Citation

- APA: Henrik Lindqvist, CFA. (2026). SOFR-ESTR Mark-to-Market Resetting Cross-Currency Basis Swap Conventions. FXMacro Wire. https://fxmacrowire.com/wire/sofr-estr-mtm-resetting-xccy-basis-swap-conventions
- Canonical article: [SOFR-ESTR Mark-to-Market Resetting Cross-Currency Basis Swap Conventions](https://fxmacrowire.com/wire/sofr-estr-mtm-resetting-xccy-basis-swap-conventions)
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