"Core argument: The gilt yield that HM Treasury cares about is not actually set by the Treasury — it emerges from a vast derivatives market that the government has no direct control over, yet must always bail out when it fails. From an MMT perspective, this is a political choice, not an economic necessity.
**The four key instruments explained:**
- **Repos** — allow hedge funds to borrow against gilts to fund leveraged trades. Hedge fund net repo borrowing hit a record ~£100bn in late 2025, much of it financing the "basis trade" (arbitraging small price gaps between cash gilts and gilt futures).
- **Gilt futures** — standardised contracts whose prices feed back into cash gilt yields via arbitrage. Futures markets don't discover "true" yields; they aggregate guesses about what the Bank of England will *choose* to do with rates.
- **STRIPS** — gilts decomposed into individual cash flows traded separately, creating a fragmented zero-coupon yield curve that the Treasury doesn't control and that serves mainly pension funds and arbitrageurs.
- **Swaps** — interest rate swaps have largely *displaced* gilt yields as the benchmark for real-economy borrowing (mortgages, corporate bonds), yet HMT has no seat at that table either. The 10-year gilt-swap spread was around 60 basis points in mid-2025, well above the normal 15–20bp range.
**The 2022 LDI crisis as proof of concept:** When the mini-budget spiked gilt yields, pension funds using LDI strategies faced unsustainable margin calls, triggering forced gilt sales of over £36bn. The Bank of England had to step in and buy £19.3bn of long-dated gilts. The article argues this wasn't a market failure — it was the logical result of a *state-designed* system that privatises gains and socialises losses.
**The MMT critique:** The $846 trillion in global OTC derivatives is not a measure of economic value but of "speculative churn." Derivatives at this scale divert talent and capital from productive activity. The state is always the ultimate backstop — so it should have explicit authority to prevent crises rather than just clean them up. Options include mandatory clearing, minimum repo haircuts, or more radically, yield curve control (fixing the entire gilt curve directly).
**The bottom line:** Gilt yields — which determine UK government borrowing costs, mortgage rates, and corporate debt pricing — are set by an unaccountable, largely algorithmic derivatives bazaar. This is the result of four decades of deliberate deregulation and financialisation, not economic necessity. The constraint on change is political will, not operational capacity."
It's pretty much down to Claude. As I suggested on X, it might be the sort of thing that could be an introductory chapter to this article.
I have my concerns about AI, but I've been 'playing' with 3 different versions to see how they get on with monetary operations - Copilot, Claude and Ellydee, which is less well known. It has taken very little prompting from me to get a good description of how the fiat money system works from both Copilot and Ellydee.
Summary by Claude, what do you think -
"Core argument: The gilt yield that HM Treasury cares about is not actually set by the Treasury — it emerges from a vast derivatives market that the government has no direct control over, yet must always bail out when it fails. From an MMT perspective, this is a political choice, not an economic necessity.
**The four key instruments explained:**
- **Repos** — allow hedge funds to borrow against gilts to fund leveraged trades. Hedge fund net repo borrowing hit a record ~£100bn in late 2025, much of it financing the "basis trade" (arbitraging small price gaps between cash gilts and gilt futures).
- **Gilt futures** — standardised contracts whose prices feed back into cash gilt yields via arbitrage. Futures markets don't discover "true" yields; they aggregate guesses about what the Bank of England will *choose* to do with rates.
- **STRIPS** — gilts decomposed into individual cash flows traded separately, creating a fragmented zero-coupon yield curve that the Treasury doesn't control and that serves mainly pension funds and arbitrageurs.
- **Swaps** — interest rate swaps have largely *displaced* gilt yields as the benchmark for real-economy borrowing (mortgages, corporate bonds), yet HMT has no seat at that table either. The 10-year gilt-swap spread was around 60 basis points in mid-2025, well above the normal 15–20bp range.
**The 2022 LDI crisis as proof of concept:** When the mini-budget spiked gilt yields, pension funds using LDI strategies faced unsustainable margin calls, triggering forced gilt sales of over £36bn. The Bank of England had to step in and buy £19.3bn of long-dated gilts. The article argues this wasn't a market failure — it was the logical result of a *state-designed* system that privatises gains and socialises losses.
**The MMT critique:** The $846 trillion in global OTC derivatives is not a measure of economic value but of "speculative churn." Derivatives at this scale divert talent and capital from productive activity. The state is always the ultimate backstop — so it should have explicit authority to prevent crises rather than just clean them up. Options include mandatory clearing, minimum repo haircuts, or more radically, yield curve control (fixing the entire gilt curve directly).
**The bottom line:** Gilt yields — which determine UK government borrowing costs, mortgage rates, and corporate debt pricing — are set by an unaccountable, largely algorithmic derivatives bazaar. This is the result of four decades of deliberate deregulation and financialisation, not economic necessity. The constraint on change is political will, not operational capacity."
Wow, thank you George, a great precis, certainly a lot easier to read. Nice job making a complex subject human readable.
It's pretty much down to Claude. As I suggested on X, it might be the sort of thing that could be an introductory chapter to this article.
I have my concerns about AI, but I've been 'playing' with 3 different versions to see how they get on with monetary operations - Copilot, Claude and Ellydee, which is less well known. It has taken very little prompting from me to get a good description of how the fiat money system works from both Copilot and Ellydee.