While funding rates are the main driver for many Eurex futures rolls, the Bund and Shats calendar spreads are different. Their performance is primarily determined by the evolution of the cheapest-to-deliver (CTD) yield curve and relative value dynamics, making them directional to yields.

With both the Federal Reserve and European Central Bank expected to remain on hold, forward financing rates are stable. This removes central bank policy as a key driver for the upcoming bond futures roll, elevating the importance of technical factors like investor positioning and repo market specifics.

Contrary to historical norms where Eurex futures lack delivery option value, the German Buxl (30-year) future currently presents some. This is driven by potential Cheapest-to-Deliver (CTD) switches, particularly to a lower coupon bond in a sell-off, creating an asymmetric upside risk for the delivery option's value.

Unlike other Eurex futures using a 6% notional coupon, the Buxel contract's unique 4% coupon makes it highly sensitive as German yields approach this level. Despite a large delivery option value, the Buxel future appears 8-10 cents cheap versus fair value, presenting a potential trading opportunity, albeit one requiring caution in the current volatile market.

The sell-off in 30-year German yields has increased the probability of the Buxel futures' 'Cheapest to Deliver' (CTD) bond switching. This is not a trivial event; such a switch would alter the future's price sensitivity (delta) by approximately 35%, posing a significant and potentially unmanaged risk for investors who are not dynamically hedging their positions.

The sharp sell-off in short-term US yields was magnified by technical dynamics, not just fundamentals. Pre-existing long positions and systematic selling from Commodity Trading Advisors (CTAs), triggered when yields broke the 200-day moving average, created a snowball effect that pushed yields higher.

A switch in the cheapest-to-deliver (CTD) bond for Eurex Buxel futures could cause a massive 35% change in the contract's DV01 (a measure of interest rate risk). This presents a significant hedging risk for investors who are not dynamically managing their exposure, as the duration gap between the current and competing CTD bonds is exceptionally large.

When the Treasury does increase coupon issuance, it will concentrate on the front-end and 'belly' of the curve, leaving 20 and 30-year bond auctions unchanged. This strategy reflects slowing structural demand for long-duration bonds and debt optimization models that favor shorter issuance in an environment of higher term premiums.

The decision to delay increases in coupon auction sizes until at least August 2027 creates a significant funding gap that must be filled with short-term debt. This policy shift will force a greater reliance on T-bills, with net issuance projected to hit $790 billion in 2027 alone, pushing the T-bill share of total debt from ~22% to 25% by 2028.