Profitable Long-Term Investments: Where and How to Invest

The investment with the best long-term track record is diversified global equities, but they also fall the most; Treasury bills and bonds currently yield less than inflation. In October 2026 Spain's CPI stands at 4.9%, 12-month Treasury bills (Letras del Tesoro) pay 3.026% and the 10-year bond 4.06%. Every profitable investment carries some risk: what you can do is choose which risk to take and spread it. Last reviewed: 16 October 2026. For this year's outlook and a portfolio by profile, see our guide to where to invest in 2026 (in Spanish).

Why invest for the long term?

Inflation keeps eroding idle savings. On 14 October the National Statistics Institute (INE) published a September CPI of 4.9% (3.1% core), and on 10 September the ECB raised rates to 2.50% on the deposit facility. Over the long term, staying invested for years reduces the weight of short-term volatility, lets you benefit from compound interest and, in funds, defer tax.

Characteristics of a profitable long-term investment

• Positive real return. It is measured after deducting inflation and tax, not before.
• Risk you can live with. What matters is not only how much it can rise, but how much it can fall without you abandoning your strategy.
• Liquidity and taxation. Knowing how quickly you can get your money back and how gains are taxed: in Spain, the savings base of personal income tax (IRPF) runs from 19% (up to €6,000) to 30% (from €300,000).

Where to invest for the long term?

Equities and index funds

A global index fund tracks an index at low cost and spreads your money across thousands of companies. The MSCI World has had years of +28% (2019) and −17.73% (2022), so it only works with a long horizon and a tolerance for seeing falls. Transfers between funds are not taxed and, when you redeem, only the gain is taxed. Compare them with ETFs in our guide to ETFs versus index funds (in Spanish).

Treasury bills and bonds

They offer a more predictable outcome if you hold them to maturity, but today they do not beat inflation: with CPI at 4.9%, 12-month bills have an approximate real return of −1.8% and the 10-year bond −0.8%, before tax. They are a stability tool, not a growth tool. More in is investing in Treasury bills safe? (in Spanish).

Property investment

Residential rents yielded an average of 6.7% gross in the first quarter of 2026, according to idealista, compared with 7.3% a year earlier. It is a gross figure: before tax, community fees, maintenance and periods without a tenant. Second-hand housing rose 12.9% over the last year (INE, Q2 2026), and buying property concentrates a lot of capital in a single asset and a single location.

Alternative investment: crowdfactoring

Crowdfactoring lets you finance invoices and promissory notes already issued by SMEs and self-employed workers and get your capital back when the debtor pays, over terms of 30 to 180 days. It is not a long-term investment in itself: because maturities are short, anyone using it in a long-term strategy reinvests what they get back.

Zero risk does not exist: the debtor may pay late, not pay or dispute the invoice, and the discount rate on each transaction is neither fixed nor guaranteed. Inversa is not a credit institution and does not belong to any guarantee fund. More on who bears the risk of non-payment (in Spanish).

How to choose your long-term investment strategy

• Define your horizon. How long you can leave the money untouched: 5, 10 or 15 years. The longer it is, the more room you have to withstand falls.
• Match the risk to your profile. If a 20% fall would make you sell, you need less equity than you think.
• Diversify across assets that behave differently. That smooths the falls. How much capital you need to do it properly is explained in how much money do you need to diversify a portfolio? (in Spanish).
• Calculate before you invest. With the compound interest calculator you can see how capital grows with regular contributions, and financial independence explains the long-term goal (both in Spanish).

How much can a monthly contribution grow

This example illustrates the effect of compound interest with €200 a month. It assumes a constant net annual return, before inflation and tax; it is not a forecast, because markets do not return the same every year.

The gap between 3% and 7% widens the longer time passes. That is why fund costs and starting early matter.

Common mistakes when investing for the long term

• Selling in the middle of a fall. It turns a temporary loss into a permanent one.
• Concentrating capital in a single asset, sector or country.
• Ignoring costs and tax. A high fee reduces the result every year.
• Investing money you may need soon. The emergency fund is kept separate and is not invested in invoices or in the stock market.

How to get started, step by step

1. First set aside an emergency fund of three to six months of expenses in a liquid product.
2. Set the goal and the time frame: a home deposit in 5 years is not invested like a retirement in 25.
3. Choose a few products that are cheap and easy to understand, and spread your capital across them.
4. Automate a monthly contribution so you do not depend on picking the right moment.
5. Review the portfolio once or twice a year and rebalance it if an asset has grown too much.

What role Inversa can play in a long-term strategy

Inversa works with short-maturity transactions, from €20 and with no fees for the investor. It can complement a portfolio of funds or fixed income if you reinvest what you get back and spread your capital across many transactions. Inversa Communities let a company open the financing of its invoices to its circle of trust (employees, family, customers). None of these options replaces a diversified portfolio or your emergency fund.

Frequently asked questions

What is the most profitable long-term investment?

Historically, diversified global equities: the MSCI World returned 9.02% a year since 1987 and 13.37% a year over the last ten years (in US dollars, before costs, as of 30/09/2026). It is also the one that falls the most: −17.73% in 2022. Past performance does not guarantee future results.

Which investment protects best against inflation today?

With CPI at 4.9% (INE, September 2026), neither Treasury bills (3.026% at 12 months) nor the 10-year bond (4.06%) beat it before tax. Equities and property have a better chance of doing so over the long term, but with a risk of losses.

How many years do you need to invest for stock market risk to be lower?

No time frame removes the risk. In the annual MSCI World series between 2012 and 2025 there were three negative years (2015, 2018 and 2022). A longer horizon gives more room to recover from falls, but it does not ensure it.