The Simple Portfolio Most People Should Just Use

In the world of finance, complexity is often used to sell products. Expensive fund managers and complex hedge strategies make investing feel like it is reserved for the elite.

But for the individual investor, the opposite is true. Complexity is the enemy. Simplicity is the engine of wealth.

Babylon's Third Cure teaches us to "Make thy gold multiply." It doesn't suggest that you should try to outsmart every merchant in the marketplace. It simply says to put your surplus to work. Today, the most effective way to do that is through a low-cost, passive index fund portfolio.

What is Passive Index Investing?

An index fund is a type of mutual fund or ETF that aims to match the performance of a specific market index—like the S&P 500 in the US or the FTSE All-Share in the UK.

When you buy a global index fund, you aren't trying to pick the "best" stock. You are buying a small slice of every major company in the world.

The Three Pillars of a Simple Portfolio

For most people, a portfolio only needs three things:

Global Equities (Stocks): A low-cost index fund that tracks the whole world. This gives you ownership in thousands of companies from Apple and Microsoft to emerging market firms. This is your growth engine.
High-Quality Bonds: These act as the "ballast" of your ship. When the stock market gets stormy, bonds generally hold their value better. See our guide on Bonds and Stability.
Cash/Liquid Assets: Your financial safety net.

The "100 Minus Age" Rule

A common starting point for your asset allocation (how much you put into stocks vs. bonds) is to subtract your age from 100.

If you are 30: 70% in stocks, 30% in bonds.
If you are 60: 40% in stocks, 60% in bonds.

This naturally makes your portfolio more conservative as you approach retirement—what we call the Sixth Cure: Insuring a future income.

Why Simple Wins

There are three reasons why this approach beats the experts over the long term:

Low Costs: Every pound you pay in management fees is a pound that doesn't compound. Most index funds cost 0.1% to 0.2% per year, compared to 1% to 2% for active funds.
Diversification: You are "guarding thy treasures from loss" (Babylon's Fourth Cure) by not putting all your eggs in one basket. If one company fails, it is only a tiny fraction of your portfolio.
Behavioral Ease: It is much easier to stay the course when your portfolio is simple and requires almost no maintenance.

The Long-Term Projection

The goal of this strategy is to turn your monthly contributions into a significant retirement fund. But what does that look like in practice?

By using our Pension Calculator, you can see how even a modest monthly contribution into a global index fund can grow over 20 or 30 years. It’s not about finding a "get-rich-quick" scheme; it’s about the patient compounding of the entire global economy.

Next Steps

If you are ready to move from saving to investing, your next stop should be our Investing Hub. We’ve curated a reading path that takes you from the absolute foundations to more advanced topics like tax efficiency.

Remember: you don't need to be a genius to build wealth. You just need a simple plan and the discipline to follow it.

Ready for more? Explore our deep dive on Owning a Piece of the Future.