For years, Spanish Treasury bills (Letras del Tesoro) were an almost invisible product for retail savers. With interest rates near zero, they offered nothing a current account didn’t already provide. That period is over. Since the European Central Bank raised rates and kept them elevated, buying short-term Spanish government debt has become a real option for anyone seeking return without market risk, and without paying anyone a fee along the way.
Interest has grown so quickly that many people have jumped in without fully understanding how the mechanics work. It’s worth spending ten minutes on that before moving any money.
What a Treasury bill actually is
A Treasury bill is, at its core, a short-term loan you make to the Spanish state: 3, 6, 9 or 12 months. In exchange, the state commits to returning your capital at maturity along with interest.
Unlike a bond, a bill doesn’t pay periodic coupons. It works on a discount basis: you buy it below its face value (typically 1,000 euros) and at maturity you receive the full face value. The difference between what you paid and what you receive is your return.
For example, if you buy a 12-month bill for 970 euros and get 1,000 euros back at maturity, you’ve earned 30 euros on a 970-euro investment — roughly a 3.1% annual return, with no additional cost if you hold the bill to term.
What makes Treasury bills attractive isn’t just the yield itself but their nature. This is debt issued by the Kingdom of Spain, backed by the state’s capacity to collect taxes. It isn’t a product from a private entity that can go bankrupt; the credit risk is, in practice, about as low as a retail saver can access in euros.
How the yield gets set
The yield on Treasury bills isn’t set arbitrarily by the Treasury. It’s determined in periodic auctions, usually twice a month, where banks, investment funds and individuals all take part. Each participant submits a bid indicating how much they’re willing to pay for a given face value, and the final price emerges from the intersection of those bids and the amount of debt the Treasury needs to place.
This has an important practical consequence: the yield on Treasury bills changes from auction to auction, moving in step with expectations about ECB interest rates. If the market anticipates rates falling, yields offered in upcoming auctions tend to shrink. If rates are expected to hold or rise, the opposite happens.
That’s why asking “what are Treasury bills paying right now?” doesn’t really make sense as a fixed figure. What matters is checking the result of the most recent auction for the term you’re interested in, published on the Spanish Treasury’s website, before deciding whether the next one is worth entering.
As an individual, you have two ways to take part in an auction: a non-competitive bid, where you accept whatever average price results from the auction without risking being shut out, and a competitive bid, where you set the maximum price you’re willing to pay, accepting the risk that your bid won’t be accepted if the cut-off price ends up lower. For a saver without advanced market knowledge, the non-competitive option is almost always the more sensible choice.
How to buy them, step by step
There are three ways to buy Treasury bills, and they are not equivalent in cost or convenience.
Through the Bank of Spain. This is the cheapest channel: no purchase fee and no custody fee. It requires opening a Cuenta Directa (Direct Account) on the Spanish Treasury’s electronic site, a process that can be completed online with a digital certificate, electronic ID or Cl@ve, or in person at a Bank of Spain branch. Once the account is open, purchase orders are placed directly through the platform, specifying the desired face-value amount.
Through your regular bank. Most banks let you buy Treasury bills through online banking, but nearly all of them charge a purchase fee and, in some cases, a custody or maintenance fee. These fees can eat into a meaningful share of the return, especially on shorter terms where the margin is already thin.
Through a broker. Some online brokers offer access to the secondary market for government debt, where previously issued bills can be bought and sold before maturity. This is useful if you need liquidity before the original term ends, but it means accepting whatever the market price happens to be at that moment, which can be better or worse than the issue price.
In all three cases, the general process is the same: you choose the term (3, 6, 9 or 12 months), decide the face-value amount you want to subscribe (minimum 1,000 euros, in multiples of that amount), and submit the order before the relevant auction’s deadline. The money is debited from your account on settlement day, and at maturity the full face value is credited automatically.
Taxes: what you actually keep
Returns on Treasury bills are taxed as investment income within the savings tax base, the same as interest from a deposit or a money market fund. Current brackets are: 19% up to 6,000 euros of savings income, 21% between 6,000 and 50,000 euros, 23% between 50,000 and 200,000 euros, 27% between 200,000 and 300,000 euros, and 28% above that.
One important nuance: unlike bank deposits, Treasury bills bought through the Bank of Spain’s Direct Account are not subject to withholding tax at the time. This doesn’t mean the return is tax-exempt — it means the full amount is declared in the following year’s income tax return, and the tax is paid then rather than upfront. For many savers this is a short-term liquidity advantage, but it’s worth keeping in mind so you’re not caught off guard at filing time, and setting the corresponding amount aside.
If you buy Treasury bills through your bank or a broker, withholding may apply depending on the channel. It’s worth confirming this before you invest so your expectations aren’t thrown off.
Treasury bills versus other alternatives
Compared with a fixed-term bank deposit, Treasury bills usually offer a similar or higher yield, with the advantage that credit risk sits with the state rather than with a specific bank’s solvency. The Deposit Guarantee Fund protects bank deposits up to 100,000 euros per institution and account holder, but Treasury bills don’t need that protection: if you don’t trust the Kingdom of Spain’s ability to pay, where you keep your savings is the least of your problems.
Compared with a money market fund, the main difference lies in management and taxation. A money market fund diversifies across multiple issuers and maturities, is professionally managed, and allows fund-to-fund transfers without triggering taxation — a valuable mechanism under Spanish tax law. Treasury bills, by contrast, are a single instrument with no diversification and no active management, but also no management fee whatsoever: what you see at auction is what you get.
Compared with a high-yield savings account, Treasury bills require locking up the money until maturity (barring a sale on the secondary market), while a savings account offers immediate access. In exchange, Treasury bills don’t depend on a bank’s temporary promotional rate, which can disappear at any moment.
None of these options is categorically better. The right choice depends on how long you can go without the money, whether you value tax simplicity or direct control more, and how much extra yield is worth giving up immediate liquidity for.
Who they make sense for (and who they don’t)
Treasury bills make sense for money you won’t need during the chosen term and that, in the meantime, you don’t want exposed to stock market volatility: the emergency fund beyond its most liquid layer, savings set aside for a future purchase, or the conservative slice of a diversified portfolio.
They don’t make sense as a substitute for long-term investing. Their yield, while attractive compared with the rock-bottom rates of the last decade, still falls short of what equities have historically delivered over ten-year horizons or longer. Nor are they the right choice if you might need the money before maturity and aren’t clear on how the secondary market works, where the price for an early sale can end up lower than what you paid.
It’s also not worth chasing the yield from the latest auction as though it were a vanishing opportunity. Conditions change every couple of weeks, and the decision to invest in Treasury bills should be driven by your time horizon and need for safety, not by a headline about “the highest yield in years.”
Used with that discipline, Treasury bills are a solid, low-cost tool for a specific slice of your savings. They don’t promise to make you rich, and that’s precisely their value: they do exactly what they say, no more and no less.
