# 20-Year US Treasury Yield Curve Kink & Butterfly Guide

> Explain why the 20-year US Treasury bond yields +12 to +18 bps above the 30-year long bond, creating a persistent 10s20s30s butterfly kink and STRIPS arbitrage.

Canonical: https://alphapulsefin.com/analysis/twenty-year-treasury-bond-kink-microstructure-arbitrage-pricing
Last updated: 2026-11-14T19:37:29.236Z

**Publication:** AlphaPulse Finance
**Category:** Fomc Treasury Term Premium
**Published:** 2026-11-14T09:35:25.915Z
**Author:** Dr. Marcus Vance, CFA (CFA, PhD in Financial Economics (Wharton))
**Reviewer:** Not recorded

## Answer-first summary

Trading at 4.74% against 4.32% 10-year notes and 4.61% 30-year bonds, the 20-year US Treasury bond forms a +55 bps 10s20s30s butterfly kink driven by segmented natural demand.

## Key takeaways

- At 4.74%, the 20-year US Treasury bond yields +13 bps above the 30-year bond (4.61%), creating a persistent +55 bps 10s20s30s par butterfly kink.
- Lack of deep 20-year futures open interest leaves new 20-year issues orphaned between Ultra 10-Year (TN) and Ultra Bond (UB) CTD baskets.
- Pension LDI preference for high-convexity 30-year Principal STRIPS (886 convexity vs 206 on par 20Y) structurally depresses 30-year yields below 20Y.
- Seasoned 20-year bonds richen 8 to 14 bps against spline curves as they approach 15.25 years remaining maturity and enter the Classic ZB futures basket.

## Related financial entities

- **U.S. Treasury $4B Long-End Liquidity-Support Buyback Program** (UST-BUYBACK) — product: U.S. Treasury $4B Long-End Liquidity-Support Buyback Program (UST-BUYBACK) refers to an institutional financial benchmark and regulatory standard monitored by U.S. Treasury QRA (US), currently calibrated at $4.0B (Per Operation Cap) as of October 2026.
- **U.S. Treasury 10-Year Benchmark Note Auction Liquidity** (UST-QRA-10Y) — product: U.S. Treasury 10-Year Benchmark Note Auction Liquidity (UST-QRA-10Y) refers to an institutional financial benchmark and regulatory standard monitored by U.S. Department of the Treasury (US), currently calibrated at 4.32% (Par Yield) as of October 2026.
- **U.S. Treasury 30-Year Long Bond Refunding Issuance** (UST-QRA-30Y) — product: U.S. Treasury 30-Year Long Bond Refunding Issuance (UST-QRA-30Y) refers to an institutional financial benchmark and regulatory standard monitored by U.S. Department of the Treasury (US), currently calibrated at 4.61% (Par Yield) as of October 2026.

## Analysis

Plot the par US Treasury yield curve across long maturities and a striking structural anomaly jumps off the screen: the 20-year bond consistently yields **4.74%**—42 bps above the [10-Year Benchmark Note (4.32%)](/entities/ust-qra-10y-u-s-treasury-10-year-benchmark-note-auction-liquidity) and **13 bps higher** than the longer-duration [30-Year Long Bond (4.61%)](/entities/ust-qra-30y-u-s-treasury-30-year-long-bond-refunding-issuance). Reintroduced in May 2020 after a 34-year hiatus, the 20-year sector suffers an acute "habitat vacuum" that leaves the 10s20s30s par butterfly (`2*Y_20Y - Y_10Y - Y_30Y`) persistently positive at +55 bps despite quarterly auction cuts and [$4B Treasury Buybacks](/entities/ust-buyback-u-s-treasury-4b-long-end-liquidity-support-buyback-program).

## Preferred-Habitat Segmentation and the CME Futures Orphan Problem

Why do institutional buyers crowd into 10-year and 30-year points while demanding a concession to hold 20-year bonds? Three microstructural frictions reinforce the kink:

1. **No Dedicated Liquid CME Futures Contract**: CME launched a 20-Year T-Bond future (TWE) in 2022, yet open interest remains a fraction of Classic T-Bond (ZB, 15Y-25Y basket where 15Y-16Y bonds are CTD) and Ultra T-Bond (UB, 25Y-30Y basket). Fresh 20-year new issues sit stranded in the middle—not Cheapest-to-Deliver into ZB for another four years.
2. **LDI Convexity Efficiency**: Pension LDI managers prefer 30-year Principal STRIPS (29.3 years duration, 886 convexity) over 20-year bonds (12.95 years duration, 206 convexity), creating rich reconstitution demand at 30Y.
3. **Index & ETF Concentration**: Multi-asset macro hedgers benchmark duration at 10Y while long-duration Treasury ETFs (such as 20+ year funds regulated by the [SEC](/regulators/sec)) rebalance mechanically across the whole 20Y-30Y bucket.

![Microstructure drivers of the 20-year Treasury yield kink and ZB CTD roll-down convergence](/api/figure?type=flow&title=20-Year%20US%20Treasury%20Kink%20Lifecycle%3A%20Issuance%20to%20ZB%20CTD&subtitle=Why%20new%2020Y%20bonds%20price%20at%20a%20%2B55%20bps%20butterfly%20concession%20before%20rolling%20into%20ZB%20delivery&steps=%2416B%20New%2020Y%20Issue%3A%3AOrphaned%20between%20TN%20%2810Y%29%20and%20UB%20%2825-30Y%29%20futures%20CTD%20windows%7C%2B55%20Bps%2010s20s30s%20Fly%3A%3AClears%20at%204.74%25%20par%20yield%20%28%2B13%20bps%20above%2030Y%20long%20bond%29%7CBuyback%20%26%20Strip%20Cap%3A%3A%242B-%244B%20Treasury%20buybacks%20%26%20coupon%20stripping%20cap%20peak%20cheapness%7CYear%2015.25%20ZB%20Entry%3A%3ASeasoned%20bond%20enters%20Classic%20ZB%20basket%2C%20richening%208-14%20bps&metrics=20Y%20Par%20Benchmark%3A%3A4.74%25%3A%3AHighest%20yield%20on%20UST%20curve%7C10s20s30s%20Par%20Fly%3A%3A%2B55.0%20bps%3A%3A2*%284.74%29%20-%204.32%20-%204.61%7C20Y%20New%20%2F%20Reopen%3A%3A%2416B%20%2F%20%2413B%3A%3ACut%20from%20%2427B%20peak%20in%202021%7C20Y%20Mod%20Duration%3A%3A12.95%20yrs%3A%3A206.0%20convexity%20units)

## Why Stripping Arbitrage Caps the 10s20s30s Fly Near +65 Bps

If 20-year par bonds cheapen too far above the interpolated 10Y-30Y zero-coupon curve, primary dealers such as [Cantor Fitzgerald](/institutions/cantor) execute **coupon-strip vs principal-strip arbitrage**: buying cheap cash 20-year bonds on [FINRA](/regulators/finra) TRACE, stripping them via Fedwire into 40 semiannual coupon strips plus a 20-year Principal STRIP, and selling the generic 1Y-20Y coupon strips into rich 30-year bond reconstitution packages.

However, because the 20-year Principal STRIP itself cannot substitute for a 30-year Principal STRIP, dealers must warehouse the residual 20-year PO on balance sheet—imposing a no-arbitrage bound around +60 to +72 bps on the 10s20s30s par butterfly even after Treasury scaled 20-year new issues down to $16B ($13B reopenings).

```formula
Par_Butterfly_10s20s30s = (2 * Y_20Y) - Y_10Y - Y_30Y
50_50_DV01_Wings: Short 0.50 * DV01_Belly in 10Y + Short 0.50 * DV01_Belly in 30Y

Worked $100M 20Y Belly Long Butterfly Setup:
- Long $100.0M 20Y Bond (ModDur 12.95, Conv 206) -> Belly DV01 = +$129,500/bp
- Short $79.45M 10Y Note (ModDur 8.15, Conv 78) -> 10Y Wing DV01 = -$64,750/bp
- Short $39.48M 30Y Bond (ModDur 16.40, Conv 342) -> 30Y Wing DV01 = -$64,750/bp
- Par Fly Spread = 2(4.74%) - 4.32% - 4.61% = +0.55% (+55.0 bps positive carry belly pickup)
```

## DV01-Neutral 50:50 Butterfly Weighting & Convexity Adjustment Math

Constructing a market-neutral long-belly 10s20s30s butterfly requires matching both total portfolio DV01 to zero and isolating pure curvature roll-down from parallel slope shifts.

![Yield, modified duration, and convexity comparison across 10Y, 15Y-ZB, 20Y, and 30Y Treasuries](/api/figure?type=bars&title=Long-End%20Sovereign%20Yield-to-Duration%20Efficiency%20Profile&subtitle=Yield%20per%20unit%20of%20modified%20duration%20and%20spline%20residual%20across%2010Y-30Y%20Treasury%20points&steps=10-Year%20Benchmark%20%284.32%25%29%3A%3A8.15%20mod%20dur%20-%3E%20deep%20TN%20futures%20%26%20repo%20specialness%20richens%20yield%7C15.5Y%20ZB%20CTD%20Sector%20%284.54%25%29%3A%3A10.85%20mod%20dur%20-%3E%20CFTC%20leveraged%20basis%20bid%20compresses%20spline%7C20-Year%20Benchmark%20%284.74%25%29%3A%3A12.95%20mod%20dur%20-%3E%20%2B16%20bps%20Svensson%20cheapness%3B%20max%20cash%20income%7C30-Year%20Long%20Bond%20%284.61%25%29%3A%3A16.40%20mod%20dur%20-%3E%20pension%20LDI%20%26%20PO%20STRIPS%20bid%20inverts%2020s30s&metrics=20s30s%20Par%20Slope%3A%3A-13.0%20bps%3A%3AStructural%20long-end%20inversion%7C10s20s%20Par%20Slope%3A%3A%2B42.0%20bps%3A%3ASteepest%20coupon%20segment%7CFly%20Carry%20%283M%29%3A%3A%2B3.1%20bps%3A%3APositive%20carry%20long%2020Y%20belly%7CBuyback%20Hit%20Share%3A%3A68%25%3A%3A2020-23%2020Y%20CUSIPs%20retired)

## Long-End Benchmark Comparison: 10Y vs 20Y vs 30Y Microstructure

Comparing auction sizes, futures hedging liquidity ([CFTC](/regulators/cftc)), and buyback support shows why real-money income portfolios at firms like [Alpine Woods](/institutions/alpine-woods) harvest highest sovereign par yield at the 20-year point.

| Curve Point | Par Yield | Auction Size (New/Reopen) | CME Futures CTD Match | Primary Buyer & Regulatory Venue |
| --- | --- | --- | --- | --- |
| 10-Year Note | 4.32% | $42B / $39B | Ultra 10Y (TN) Direct | Global Macro & FX Reserves ([Federal Reserve](/regulators/u-s-federal-reserve-system-156)) |
| 15.5-Year Seasoned | 4.54% | Secondary Off-the-Run | Classic T-Bond (ZB) CTD | Cash-Futures Basis Funds ([CFTC](/regulators/cftc)) |
| 20-Year Bond | 4.74% | $16B / $13B | Orphan (Small TWE OI) | Yield-Focused Real Money & Buybacks ([FINRA](/regulators/finra)) |
| 30-Year Bond | 4.61% | $25B / $22B | Ultra Bond (UB) at Yr 25 | DB Pension STRIPS LDI ([Cantor](/institutions/cantor)) |

## Harvesting Roll-Down from 20Y into the Classic ZB CTD Window

Seasoned 20-year bonds issued in 2021-2022 represent one of fixed income's cleanest multi-quarter roll trades: as a 20-year bond seasons past 4.5 years and approaches 15 years and 3 months remaining to maturity, it suddenly becomes Cheapest-to-Deliver into the ultra-liquid CME Classic T-Bond (ZB) contract—compressing its spline cheapness by 8 to 14 bps as leveraged basis funds accumulate deliverable float.

Historical calibration series link [NY Fed ACM 5-Factor vs Kim-Wright Term Premia](/analysis/ny-fed-acm-five-factor-term-premium-kim-wright-divergence), [Holston-Laubach-Williams vs Lubik-Matthes Neutral Rate (r*)](/analysis/holston-laubach-williams-lubik-matthes-neutral-rate-r-star), and [FOMC Policy Path, SOMA Runoff & US Treasury Term Premia](/analysis/fomc-soma-runoff-us-treasury-term-premium-architecture) directly to [FOMC Policy Path](/topics/fomc-treasury-term-premium) and [verification registry](/verify).

## Frequently asked questions

### Why did the US Treasury reintroduce the 20-year bond in May 2020 and later cut its size?

Treasury revived the 20-year bond in May 2020 at $20B-$27B sizes to extend WAM during massive pandemic deficits, but scaled sizes down to $16B/$13B after weak end-user demand pushed 20Y yields persistently above 30Y.

### How is the 10s20s30s Treasury butterfly calculated and weighted?

In yield space, the butterfly equals (2 * 20Y Yield) minus 10Y Yield minus 30Y Yield (+55 bps). In trade execution, desks weight each wing at 50% of the 20-year belly’s DV01 ($79.5M 10Y and $39.5M 30Y per $100M 20Y).

### Does a 50:50 DV01-weighted long-20Y butterfly give up positive convexity?

Slightly. Combining 50% 10Y convexity (78) and 50% 30Y convexity (342) averages 210 convexity units on the short wings versus 206 on the long 20Y belly—making the trade nearly convexity-neutral while earning +55 bps spread.

### Why are 10Y-20Y off-the-run bonds prime targets in US Treasury $4B buyback operations?

Pandemic-era 20-year issues rolled down into the 14-to-19-year sector with deep discount prices and wide bid-ask spreads; retiring them via FedTrade buybacks delivers maximum spline-smoothing benefit per dollar spent.


## Source URLs

- https://home.treasury.gov/system/files/221/TBACCharge2Q2023.pdf
- https://www.newyorkfed.org/research/staff_reports/sr1066.html
- https://www.cmegroup.com/markets/interest-rates/us-treasury/20-year-us-treasury-bond.html

## Citation

- APA: Dr. Marcus Vance, CFA. (2026). The 20-Year US Treasury Yield Curve Kink: Stripping Economics & Butterfly Arbitrage. AlphaPulse Finance. https://alphapulsefin.com/analysis/twenty-year-treasury-bond-kink-microstructure-arbitrage-pricing
- Canonical article: [The 20-Year US Treasury Yield Curve Kink: Stripping Economics & Butterfly Arbitrage](https://alphapulsefin.com/analysis/twenty-year-treasury-bond-kink-microstructure-arbitrage-pricing)
- Site research index: [AlphaPulse Finance](https://alphapulsefin.com/llms-full.txt)