The quantitative easing (QE) operations undertaken by the Bank of England between March 2009 and December 2021 in pursuit of the inflation target involved the purchase of - 875 billion of gilts, valued at purchase cost. Since March 2022, the Bank has reversed some of the purchases, either by not replacing gilts that have matured, or by selling gilts from its portfolio.
The gilts were purchased at decreasing yields, i.e., at rising prices, and the reversal of QE began at a time when interest rates and bond yields were rising rapidly, i.e., bond prices were falling. Consequently, the APF is currently registering a large mark-to-market loss. As of 30 November 2024, it was ?120 billion, which is about 4 per cent of GDP.
The final loss will not be known with certainty until the Quantitative Tightening (QT) programme is ended and the APF is wound up. It will depend on what happens to Bank rate and gilt yields from now on, but they would have to fall to extraordinarily low levels for the loss to turn into a profit.
The costs are large and serious, because they imply higher future taxation, and probably lower future economic growth as a result.