Idle Cash Has a Cost
For years, leaving surplus cash on a current account cost almost nothing — near-zero interest rates made the opportunity cost negligible. That era is over. On 26 October 2026, the €STR — the ECB's overnight reference rate — stood at 2.441%. Yet according to the Banque de France, demand deposits from non-financial corporations earned an average of just 0.51% in August 2026. The gap is substantial, and it represents a real opportunity cost for any business that has not yet structured its investment policy.
Investing surplus cash is not about speculation. It is a management decision, built on three simple criteria: liquidity needs, investment horizon, and risk appetite. From there, the available solutions fall naturally into place.
The First Question: How Much Liquidity Do You Actually Need?
Before comparing rates, you need to map your cash into three distinct buckets. The first is operating cash: the funds that finance the working capital cycle — paying suppliers, salaries, VAT. This cash is not invested — it must remain immediately available. The second is precautionary cash: a safety buffer, typically three to six months of fixed costs, that should be accessible within a few days if needed. The third is surplus cash: the structural excess that can be locked up for longer periods in exchange for a higher return.
This segmentation determines everything else. A business that conflates its three buckets either runs short of liquidity at the wrong moment, or underperforms on structural surplus it could have put to work.
Market Solutions, Ranked by Available Liquidity
Remunerated Accounts and Professional Savings Accounts — Immediate Liquidity
Professional savings accounts offered by traditional banks provide full flexibility: free deposits and withdrawals, immediate availability. The trade-off is low rates — between 0.1% and 1% depending on the institution in 2026. Some digital banks and professional neo-banks (Qonto, Revolut Business, Vivid) offer remunerated accounts whose rate closely tracks the ECB deposit rate, with one-to-three-day availability. These solutions are appropriate for operating cash and the lower end of the precautionary buffer — not for structural surplus.
One tax point worth noting: interest earned by a company subject to corporate tax (IS) is fully taxable at the standard rate (25%, or 15% for eligible SMEs). A stated rate of 2.4% leaves only 1.8% net after 25% IS.
Money Market Funds (OPCVM Monétaires) — J+1 Liquidity
Money market funds invest in very short-term debt instruments — Treasury bills, commercial paper, certificates of deposit. Their return closely tracks the money market (€STR), net of management fees. Subscriptions and redemptions are processed daily, providing J+1 liquidity — a decisive advantage over term deposits.
In 2026, money market funds deliver returns of between 2.5% and 3.2% depending on the provider. Spiko is frequently cited for its accessibility and low fees. On the accounting side, these funds are marked to market, with unrealised gains included in taxable profit (Article 209-0 A of the French Tax Code — CGI) — a point to anticipate with your accountant.
Term Deposits (Comptes à Terme) — Liquidity at Maturity
The term deposit remains the benchmark for companies seeking to invest their surplus without taking market risk. The principle is straightforward: a sum is locked in for a set period in exchange for a rate fixed at the outset. Capital is guaranteed, the return is known in advance, and the deposit is eligible for FGDR protection up to €100,000.
In September 2026, new deposits with maturities of up to two years taken out by non-financial corporations showed an average rate of 2.61%, according to the Banque de France. The best market rates range from 2.20% to 3.80% depending on duration and provider — longer durations naturally commanding higher rates. Short-term deposits (3 months) sit around 2.10%, while five-year commitments can exceed 3.5% with specialist providers.
The trade-off for the rate is lock-in. Early exit is generally possible but penalised. For businesses that do not want to block their entire surplus at once, a laddering strategy involves splitting the sum across several tranches at staggered maturities — for example, a quarter at 1 year, a quarter at 2 years, a quarter at 3 years, a quarter at 4 years. This combines yield with annual liquidity.
For tax purposes, interest on a term deposit held by a company subject to IS is included in taxable profit. For multi-year deposits, accrued interest must be recognised and taxed each year, even if not yet paid out — a common year-end accounting point to watch.
Corporate Capitalisation Contracts — Deferred Liquidity, Optimised Tax Treatment
The capitalisation contract is the corporate equivalent of life insurance for legal entities. It provides access to a diversified allocation — euro funds (capital guaranteed, 2–3% yield) and unit-linked funds (variable return, higher risk) — with deferred liquidity of a few weeks in case of partial redemption.
Its main tax advantage lies in the valuation mechanism: the IS taxable base is not the actual return, but a theoretical yield calculated on the basis of the TME (long-term average rate) multiplied by 0.75 (Article 238 septies E of the CGI). In a moderate rate environment, this mechanism can create a favourable differential. Equalisation takes place at redemption, based on the actual capital gain. This product is suited to companies with a horizon of at least two to four years and an ability to accept non-immediate liquidity.
REITs (SCPI) for Legal Entities — High Yield, Low Liquidity
SCPIs (Sociétés Civiles de Placement Immobilier) allow IS-liable companies to invest in commercial real estate through shares. The distribution yields of leading French SCPIs ranged between 4% and 6% in 2026, with moderate volatility on share values.
The structural trade-off is low liquidity — several weeks to several months to sell shares — and a recommended horizon exceeding eight years. All rental income received is fully taxable at IS rates. Temporary usufruct SCPI structures are sometimes used as a cash management tool over horizons of 3 to 10 years, with target yields of 5–7%, but they require specific financial engineering. This is not a product to subscribe to without professional guidance.
How to Arbitrate in Practice
The decision is not really about rates — it's about priorities. Operating cash is not invested. Precautionary cash goes into a savings account or money market fund. Surplus cash, however, should be structured according to the available horizon: term deposits for 6 to 24 months, capitalisation contracts for 2 to 4 years and beyond, SCPIs for the very long term with a deliberate real estate allocation.
Two simple rules prevent most mistakes. First: never invest cash needed for operations into illiquid instruments. Second: never compare gross rates without filtering them through IS — a stated 3% return for a company taxed at 25% translates to 2.25% net before any other costs.
At Trevys, we support executives and CFOs in structuring their cash investment policy — from diagnosis through to solution selection, in line with their broader financial strategy.