The UK’s long term borrowing costs hit their highest level since 1998 this week, in what is fast becoming the most reliable headline in fixed income.
But the culprit this time was not an oil shock, a mini-Budget or a central bank pivot, but the parliamentary Labour Party, whose revolt against prime minister Keir Starmer has turned the long end of the Gilt curve into a real-time leadership poll.
The interest rate volatility market, however, is refusing to play along.
Implied vol on 10 and 30 year sterling rates is running at around 100 basis points (normalised, expressed in basis points per annum), against peaks near 130bp earlier this year and as high as 300bp during the 2022 Gilt crisis.
That tells a story about how this sell-off differs from the ones some observers instinctively reach for as parallels.
The volatility highs earlier this year were not just about levels. March and April crammed several fat-tailed risks into one fortnight: the closure of the Strait of Hormuz and a cluster of Federal Reserve, European Central Bank and Bank of England meetings.
Buying interest rate volatility protection in that scenario hedged against two-way uncertainty over policy. The US ceasefire with Iran — however shaky — has since drained much of that premium.
Nor does this week’s episode resemble 2022. Two structural changes are doing the work of holding long-dated volatility down, while Gilt yields spill higher.
The UK Debt Management Office has reduced its long-dated issuance, muting volatility hedging demand at the very tenor that is usually most stressed.
But the biggest structural change is the dismantling of sterling's dreaded feedback loop. Liability-driven investing leverage and forced flow risks are materially lower now, as the Bank of England requires pension schemes to hold liquidity buffers to withstand a significant move in yields.
Those structural reforms are working as intended. A long-end sell-off that would once have triggered a crisis is being absorbed as a slow grind.
The derivatives market is pricing a repricing, not a rupture.
The Labour Party should be grateful for the market's orderliness, though not mistake it for approval.