What investment funds are and how they work

Investing is one of the most effective ways to grow long-term savings, but picking specific companies, sectors, and timing takes knowledge, time, and a tolerance for risk that not everyone has or wants to take on. Investment funds emerged precisely as a response to that reality, letting you put your money to work in a diversified way without having to manage it directly.

They are a firmly established vehicle in Europe, with thousands of funds available through banks, asset managers, and online platforms, backed by a regulatory framework that offers guarantees and transparency. Here is what they are, how they work, what types exist, and what to have clear before taking the step.

What an investment fund is

An investment fund is a collective vehicle in which many people contribute money that is invested jointly, following a strategy defined by a professional management company. Each contributor receives units (or shares), whose value rises or falls depending on how the underlying assets perform.

The goal is to generate returns for unit-holders by investing in a diversified portfolio of assets: stocks, bonds, government debt, currencies, or even other funds. Diversification is the core of the model, because the impact of a bad individual investment gets diluted within the whole.

How investment funds work

When you invest in a fund, your money becomes part of a common pool managed by professionals. The management company decides which specific assets to invest in within the fund’s stated strategy, and the same team buys, sells, and rebalances the portfolio over time.

The value of each unit, known as the Net Asset Value (NAV), is calculated daily based on the market price of all the assets held by the fund. When you want to enter, you buy units at the day’s NAV. When you want to exit, you sell them on the same basis.

As a unit-holder you don’t get a vote on specific investment decisions, but the management company is required by European regulation to provide you with a document containing the key information about the fund. For UCITS funds, this document is called the KID (Key Information Document) and includes the strategy, costs, historical performance, and risk level.

Types of investment funds

Not all funds pursue the same goal or take on the same risk. These are the most common types.

Fixed income funds. They invest in bonds, treasury bills, corporate debt, and other assets with predictable returns. They offer lower risk and more modest returns, and are the typical option for conservative profiles or those looking to preserve capital.

Equity funds. They concentrate their investment in listed shares. They offer higher return potential but also higher volatility. They usually break down by geography, economic sector, or company size.

Mixed funds. They combine fixed income and equities in variable proportions. They are classified as defensive, moderate, or aggressive depending on the equity weighting.

Guaranteed funds. They guarantee that unit-holders will recover all or part of the capital invested by a specific date, provided the fund’s conditions are met. The trade-off is a limited upside.

Index funds. They replicate the behaviour of a stock index (for example, the S&P 500 or the MSCI World) without trying to beat it. They have become popular for their low fees and simplicity, and form the basis of many long-term portfolios.

Money market funds. They invest in very short-term assets such as treasury bills or deposits. They offer low returns in exchange for high stability.

Advantages and disadvantages of investing in funds

The main appeal of funds is that they give access to professional management and broad diversification with amounts that would be unfeasible otherwise. With €100 you can be exposed to hundreds of companies through an index fund, something impossible if you were buying individual shares.

There are also tax advantages worth knowing about, particularly in Spain, where transfers between funds are not taxed until you actually withdraw. This lets you change strategy without triggering a taxable event on accumulated capital gains.

The downsides exist too. Fees can erode returns over time, especially in actively managed funds with high costs. On top of that, buying and selling isn’t instant like with shares — orders execute at the end-of-day NAV, not in real time. And there is always market risk: professional management reduces specific risks, it doesn’t eliminate them.

Legal framework and supervision

Investment funds are regulated at European level by the UCITS Directive and, for alternative vehicles, by the AIFMD Directive. This framework sets requirements around management, custody, disclosure, and investor protection.

Each Member State has its own supervisor. In Spain the authority is the CNMV, in France the AMF, in Italy CONSOB. Any fund marketed within a Member State must be registered with the local authority, and that information is publicly available. At European level, the European Securities and Markets Authority (ESMA) ensures consistency across the Union.

How to start investing in funds

Before subscribing to a fund it’s worth being clear on three things: your investment horizon, the level of risk you accept, and the fees you are willing to pay. These three factors define which type of fund makes sense for you.

Funds are subscribed through banks, asset managers, and specialised fund platforms. The latter usually offer broader catalogues and more competitive fees, particularly for low-cost index funds. Minimum investment varies by fund, but many allow starting with €100 or €200 and setting up periodic contributions from very small amounts.

Periodic contributions, or scheduled purchases at regular intervals, is one of the most recommended strategies for retail investors. It reduces the impact of entry timing by spreading purchases over time and helps maintain investment discipline regardless of market swings.

The same principle applies to other asset classes. If crypto is part of your strategy, the Bitsa scheduled saving feature lets you accumulate crypto automatically from €6, with daily, weekly, monthly, or annual frequencies across 13 available assets. It is not an investment fund and doesn’t replace one, but applies the same DCA logic of spreading purchases over time.

Frequently asked questions about investment funds

How much money do I need to invest in a fund?

It depends on the fund. Many allow entry from €100 or €200, and some platforms offer periodic contributions from €50 per month. Before investing, check the fund’s prospectus for the exact minimum.

What is the difference between an investment fund and an ETF?

A traditional investment fund is bought and sold at the end-of-day NAV, while an ETF trades on the stock exchange like a share, with its price fluctuating in real time. ETFs usually have lower fees, but in Spain they lose the tax advantage of tax-free transfers that traditional funds retain.

How are investment funds taxed?

Tax treatment depends on your country of residence. In Spain, gains are taxed as savings income when you redeem units, with rates ranging from 19% to 28% depending on the amount. Transfers between funds don’t trigger tax until final redemption. In France, the flat-rate withholding tax (PFU) of 30% typically applies. In Italy, gains are generally taxed at 26%.

Is investing in funds safe?

Funds registered with a national regulator meet strict requirements on management, transparency, and custody. This does not eliminate market risk: you can lose part of the capital invested if the fund’s assets fall. Regulatory safety and investment risk are two different things.

Can I lose all my money in an investment fund?

It is extremely unlikely in diversified funds such as fixed income, mixed, or global index funds, because a total loss would require all the fund’s assets to lose their value simultaneously. In highly concentrated or specialised funds, the risk of large losses is real.