Treasury Bills are among the simplest instruments in the sterling money markets. They are short-dated government securities, issued by the Debt Management Office on behalf of HM Treasury, typically at one, three and six months, sold at a discount and redeemed at par. Most treasury investors will know the concept, but in practice T-bills remain less widely used than deposits and, for some investors, less understood. That is generally not because of risk or return. More often, it comes down to operational realities, market infrastructure and familiarity. The UK Government is now consulting on how to expand and deepen the T-bill market, including broadening participation and encouraging a more active secondary market, which suggests the market is evolving.
From a credit perspective, the attraction is straightforward enough. T-bills are direct short-term exposure to the UK Government and therefore represent one of the highest-quality short-term sterling assets. Current pricing suggests investors are not necessarily giving up much return for that quality. Recent DMO auction results showed average yields of around 3.7% for one-month bills, 3.9% for three months and just over 4.0% for six months. Against recent deposit and secured rates, that compares reasonably well. That matters, because there is still a tendency to assume that sovereign exposure must come with a material yield sacrifice and in the current market that is not always the case.
Where T-bills become less simple is in how they are actually used. Most investors do not buy them directly from the DMO. Access is typically through a broker or bank, either at the weekly auction through a Treasury Bill Primary Participant or in the secondary market. They are also securities rather than deposits, so settlement and custody arrangements are needed. In practice that often means holdings sit in a broker’s omnibus or nominee account rather than with a dedicated custodian, due to cost. None of this is especially complicated, but it is more involved than placing a deposit and for many investors that additional layer is enough to keep T-bills out of or on the fringes of their strategy.
The auction process itself is also worth understanding. Treasury Bills are issued through weekly tenders, with bids submitted competitively by price. Investors are not simply choosing whether or not to invest at a known rate, they are deciding what price to bid, which in turn determines the yield they are prepared to accept. Bid too conservatively and allocation may be easier to secure, but the yield may be less attractive than it needs to be. Bid more aggressively for yield and there is a greater chance of receiving no allocation at all. It is not an exact science, particularly when market tone shifts or demand proves stronger or weaker than expected, but nor is it random. Previous auction results, prevailing money market rates, recent bill performance, net supply and conditions in other markets can all help inform where value may lie. That is one of the reasons some investors prefer to rely on guidance from advisers or counterparties with experience of the weekly process.
Secondary market access exists through brokers and dealers, but the UK market is not as deep or liquid as some might assume. Market participants responding to the DMO consultation have pointed to the need for better two-way liquidity and a more functional repo market, while also noting that secondary activity in UK T-bills and short-term gilts is currently low because these instruments are often bought and held to maturity.
Money market funds are relevant here too, even though they are not directly comparable with a ladder of T-bills. Many treasurers will already have indirect exposure through sterling MMFs, which invest in cash instruments including Treasury bills. In that sense, T-bills are already part of the liquidity toolkit, just often one step removed.
So T-bills do look slightly underused, particularly by investors who default to deposits or MMFs, and that underuse is understandable. They are less administratively convenient than deposits, less immediately liquid than same-day funds, and the UK secondary market is historically limited in terms of breadth and secondary activity. But they are also high-quality, short-dated and currently competitive on yield. For investors, with the scale and governance to accommodate the operational side, that is enough to justify a closer look. The real obstacle is not what T-bills are, it is what is needed to use them properly.
Arlingclose advises on UK Treasury Bills, including access to the market, the financial infrastructure necessary to buy, hold and participate in weekly auctions, as well as bidding recommendations in those auctions. Outside of sterling, for those organisations with multi-currency exposure, we also provide similar advice on foreign government treasury bills. If you’d like to learn more about these services please contact us on info@arlingclose.com
21/04/2026
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