The Gilt Crisis: When UK Pensions Almost Blew Up in a Week
In September 2022 a UK tax cut announcement set off a bond market spiral that nearly toppled the country's pension system in days. The Bank of England stopped it with 19.3 billion pounds and a masterclass in what hidden leverage does to safe portfolios.
The Mini Budget That Broke the Bond Market
On September 23, 2022, the UK\'s new chancellor, Kwasi Kwarteng, announced what the government called a mini budget: roughly 45 billion pounds of unfunded tax cuts, the largest in half a century, presented without the independent fiscal forecast that normally accompanies British budgets. Investors were being asked to fund a big new deficit at the exact moment the Bank of England was raising rates to fight double digit inflation. They answered by selling gilts, UK government bonds, at a pace with no modern precedent. Yields on thirty year gilts, around 3.6 percent before the announcement, ripped past 5 percent within three trading days, a move of a size that normally takes years. The pound fell to a record low near 1.03 dollars. And then the crisis found its accelerant, in a corner of finance almost nobody outside pensions had heard of.
What LDI Actually Is
A defined benefit pension promises retirees fixed payments decades into the future. Accounting rules value those promises using bond yields: when yields fall, the promises get more expensive on paper. Through the 2010s, UK pension schemes adopted liability driven investment, LDI, to neutralize that math. The idea is to hold gilts and gilt based derivatives whose value moves opposite to the liabilities, so the funding ratio stays stable. But schemes wanted the hedge and growth assets like equities at the same time, so LDI funds delivered the gilt exposure with leverage, financing it through repo borrowing and interest rate swaps. A scheme might control three or four pounds of gilt exposure per pound of capital posted.
Leverage means margin. When gilt prices fall, the LDI fund must post more collateral. Modest moves were pre funded. The September 2022 move was not modest.
The Doom Loop
As thirty year yields spiked, collateral calls went out to hundreds of pension schemes at once, demanding cash within days. Schemes\' liquid asset of choice for raising that cash was, naturally, gilts. So falling gilt prices forced gilt sales, which pushed prices down further, which generated bigger collateral calls. By Tuesday, September 27, parts of the long dated gilt market were seizing up, and the Bank of England later told Parliament that some LDI funds were hours from default, which would have dumped their entire gilt holdings into a market with no bid.
Every margin spiral has the same geometry: the asset you must sell to raise cash is the asset whose fall is generating the calls. The gilt crisis ran that loop through the safest asset class in Britain, held by the most conservative investors in Britain, in under four days.
The Bank Steps In
On September 28, the Bank of England announced it would buy up to 65 billion pounds of long dated gilts, up to 5 billion a day for thirteen weekdays, ending October 14. The framing mattered: this was a financial stability operation, not stimulus, and it was happening while the Bank was simultaneously raising rates. On October 11 it added index linked gilts to the program after that smaller market convulsed. The governor then did something unusual, publicly refusing to extend the deadline, telling pension funds they had three days to sort themselves out. The hard deadline worked. In the end the Bank bought only 19.3 billion pounds of its 65 billion capacity, because the guaranteed backstop bid itself restored order; schemes used the window to raise cash and rebuild buffers.
| Date, 2022 | Event |
|---|---|
| September 23 | Mini budget: 45 billion pounds of unfunded tax cuts |
| September 23 to 27 | 30 year gilt yields surge from about 3.6 toward 5 percent |
| September 28 | Bank of England announces up to 65 billion of purchases |
| October 14 | Program ends; only 19.3 billion actually bought |
| October 20 | Prime Minister Truss resigns |
The Political Fallout
Markets executed the fastest government reversal in modern British history. Kwarteng was fired on October 14, most of the mini budget was scrapped, and Prime Minister Liz Truss resigned on October 20 after roughly seven weeks in office, famously outlasted by a supermarket lettuce that a tabloid had livestreamed next to her photo. The episode entered the permanent vocabulary of finance: when commentators now ask whether a government will get the Truss treatment, they mean punishment by the bond market severe enough to end an administration.
The Bottom Line
The gilt crisis proved that safe assets plus leverage equals an unsafe portfolio, and that a margin spiral can take the pension system of a G7 country from stable to near failure in four days. It also showed what a well designed backstop looks like: capped, priced as a last resort, and credibly temporary, so that 19.3 billion pounds of actual buying did the work of 65. In hindsight it was the decade\'s clearest warning about hidden leverage in boring places, and regulators worldwide have been hunting for the next LDI ever since.