Backtest by Curvo

What it is

Backtest by Curvo answers one question for somebody who holds European funds — what would this mix have done. You pick funds by name or ISIN, set the weights, choose a rebalancing rule, and get a growth curve, annual returns, drawdowns with their recovery periods, standard deviation, Sharpe ratio and a histogram of monthly returns.

What makes it work for Europe is that for the 1,212 index funds and ETFs the analysis runs on the index behind the fund rather than on the fund itself. The oldest European ETF tracking the MSCI World launched in 2005; the index series here starts on 31 December 1969. The tool takes the index, subtracts a twelfth of the fund's ongoing charge every month, and presents the result as that fund's history. The 94 actively managed funds work the other way — each carries a price series of its own and begins when the fund did. It describes itself as Portfolio Visualizer for Europe.

Around that sit a portfolio comparator, Monte Carlo forecasts driven either by historical moments or by CAPM, an efficient frontier, a minimum-investment-horizon chart and a statistics page for every index. Two things American tools rarely model appear here because the audience is European — a broker's entry fee, and Belgian transaction tax (TOB) alongside the Reynders tax on bond funds. The interface runs in nine languages.

Pricing

Free, with no paid tier and nothing withheld from anonymous visitors. Google sign-in is the only account mechanism and it buys one thing: portfolios stored server-side instead of in the browser.

Data & coverage

1,306 funds and 504 index series, read from the application's own catalogue on 14 September 2026. The funds are European-domiciled — 637 Irish ISINs, 402 Luxembourg, 99 German, 68 French, 30 Belgian, 24 Swiss and 21 British. 1,212 are index funds or ETFs and 94 are actively managed; 1,160 carry a ticker, ongoing charges run from 0.00% to 2.90%, and 55 funds have an entry fee attached.

The index side is 357 equity series, 109 fixed income, 15 crypto, 9 real estate, 8 commodity and 6 precious metals; 277 are net-total-return series, 206 gross and 21 price-only. Nine reach back to 31 December 1969 — MSCI World, USA, Europe, Pacific and Canada among them — and EUR-hedged gold starts earlier still, in January 1968. On the day checked, 421 of the 504 ended on 31 July 2026 and 24 ran to 31 August 2026.

Everything is monthly month-end data held in euros and displayed in EUR, GBP or USD. Conversions predating the euro use the ECU back to 1979 and the Deutsche Mark before that. Dividends are assumed reinvested whether or not the real fund distributes them, which the FAQ puts down to the difficulty of sourcing distribution data. Sharpe ratios use three-month Euribor as the risk-free rate, and the inflation series is the Belgian consumer price index.

Integrations

There is no public API. Charts export as CSV, PNG or SVG, each offers an embed code, and the whole simulation state is encoded in the URL, so any configured backtest is a link somebody else can open. A GraphQL endpoint exists but is undocumented and serves only geolocation, sign-in and saved portfolios. Missing funds are requested through a Google Form.

Limitations

• The vendor's business is managed investing. Curvo is a trade name of NNEK, a Dutch investment firm regulated by the AFM, and it charges 1% a year falling to 0.6% above 250,000 euros to run a portfolio for you. Five of the tool's built-in portfolio templates are Curvo's own products, and result pages carry a block inviting you to have a portfolio built for you. None of that gates the tool, and the managed service is available only to residents of Belgium with a Belgian bank account — so most of the people using the backtester could not buy it.
• Fund history before inception is synthesised for the 1,212 index funds. A 2020 fund showing a 1970 drawdown is the index with a fee subtracted, not a record of anything that happened. Perfect tracking is assumed and called negligible in the FAQ; tracking difference, securities lending and a fee that changed over the years are all outside the model. Only the 94 actively managed funds are backed by a price history of their own.
• Forty-four of the 504 index series have stopped updating, one as long ago as December 2015 and several in 2022. Nothing marks them as retired, so a comparison can silently end early.
• Monthly resolution. Drawdowns come off month-end values, so anything that fell and recovered inside a month is invisible.
• The inflation view is Belgian and lags the returns, ending 31 December 2025 against market data through July 2026. No German, Dutch or French inflation option.
• Euro-denominated by construction. GBP and USD are display conversions off a euro base, and there is no Swiss, Swedish, Danish or Polish home currency.
• Funds only. No individual shares, no direct bonds, no options, and no way to import a return series of your own.

Alternatives

Portfolio Visualizer is the tool this one models itself on, and the choice between them is geography — it works from US and Canadian tickers on a US tax and inflation model, and caps free ticker backtests at ten years. Portfolio Charts covers twelve home countries, several of them European, but models index asset classes rather than tickers, so it cannot tell you what your actual UCITS ETF would have done. Come here when the holdings you are testing have ISINs.