Does a Risk-Free Rate Really Exist? Three Hidden Risks

The risk-free rate is a theoretical convention, not an absolute guarantee. Inflation risk, sovereign risk, liquidity risk: what investors need to understand.

The “risk-free rate” is one of the most widely used concepts in finance — and one of the most misleading. In theory, it refers to the yield an investor can obtain without exposure to any uncertainty, typically through short-dated sovereign bonds. But this convention rests on fragile assumptions: it ignores inflation risk, residual sovereign risk and liquidity conditions. Treating a yield as “guaranteed” often means forgetting that the guarantee itself carries a cost. Related discussion: our account of the decision-stress simulators.

Why the current equilibrium is less stable than it appears: after a decade of near-zero rates, the rise in policy rates has temporarily restored a visible nominal yield to “risk-free” assets. This visibility creates the illusion that “risk-free” has become attractive again — even though the risks it conceals have not disappeared.

A theoretical convention, not a market reality

In academic finance, the risk-free rate serves as a reference point: it is the floor from which the risk premium of any asset is calculated. It is generally identified with the yield on short-dated sovereign bonds — three-month US Treasury bills (T-bills) or German Bunds. The implicit assumption: these issuers will never default. The argument is developed step by step in whether the risk-free rate is truly risk-free.

That assumption is debatable. According to BIS data (Quarterly Review, December 2025), public debt across G7 advanced economies averaged more than 120% of GDP at end-2025. While the probability of sovereign default remains low for the highest-rated issuers, it is not zero — and crucially, the risk does not reduce to default alone. Restructuring risk, financial repression and debt monetisation are real, even for AAA issuers.

Three risks the “risk-free” label ignores

The first is inflation risk. A Treasury bill yielding 3% in nominal terms in a 2.5% inflation environment delivers only 0.5% in real terms. According to Eurostat data (Q4 2025), eurozone core inflation stood at around 2.4%. An investor in short-dated Bunds was earning a nominal yield of roughly 2.1% — a negative real return. “Risk-free” guarantees the nominal, not purchasing power.

The second is residual sovereign risk. The 2012 Greek crisis showed that partial default on eurozone sovereign debt was possible. The spread between Italian and German 10-year bonds hovered around 120 basis points in early 2026, according to market data — a level that already incorporates credit risk, however modest. “Risk-free” is risk-free only for the highest-rated issuer, not for all sovereigns.

The third is liquidity risk. In periods of market stress, even sovereign bonds can become temporarily illiquid — as the September 2022 UK gilt episode demonstrated. The notion of “risk-free” assumes permanent liquidity that is not always available. Recognising these limits brings us back to the three functions of capital: absolute safety is an accounting convention, not an intrinsic property of any asset.

Market consensus treats the risk-free rate as a settled technical input — a model parameter, not an object of inquiry. This approach is operational within a portfolio management framework, but it can become misleading for a saver who reads “risk-free” literally. The distinction between professional convention and household reality is rarely made explicit.

What would invalidate this critical reading is a sustained return to inflation near zero combined with massive sovereign deleveraging — a scenario that would restore the “risk-free” framing as a reliable approximation. Neither IMF projections (October 2025) nor OECD projections retain this scenario over a five-year horizon.

The risk-free rate exists as a calculation convention, not as a household reality. Several rate and inflation paths remain open, but none of them removes the risks the convention conceals. The relevant question is not “what is the risk-free rate”, but “what risks are implicitly accepted by treating it as safe” — a framing that applies to understanding everyday financial choices.

Last updated — 12 July 2026