Plain Investor
10 guides

ETFs & Index Funds

Low-cost, diversified investing through funds that track the market instead of trying to beat it.

ETFs & Index Funds

How to Get Investment Exposure to AI Without Picking Individual Stocks

Betting on which individual AI company wins is genuinely difficult. Here's how broad fund categories let investors gain exposure to the trend without picking a single winner.

Sep 21, 2026 · 6 min read
ETFs & Index Funds

AI, Concentration Risk, and What It Means for Your Index Fund

A handful of large technology companies now account for an unusually large share of major market indexes. Here's what that means if you think of yourself as broadly diversified.

Sep 21, 2026 · 7 min read
ETFs & Index Funds

Active ETFs Explained: What's Driving the Shift

Active management has been migrating out of the mutual fund wrapper and into the ETF one. Here's what's driving the shift, and what it doesn't change.

Sep 21, 2026 · 7 min read
ETFs & Index Funds

Money Market Funds: Where Cash Earns a Yield

Money market funds pay a yield that tracks short-term interest rates, but they are securities rather than deposits — and the distinction matters more than most savers realise.

Sep 21, 2026 · 7 min read
ETFs & Index Funds

Thematic ETFs: The Hidden Risks of Investing in a Story

Thematic funds package a compelling narrative into a single ticker. The strategy is legitimate; the risks are structural, and most of them are visible before you buy.

Sep 21, 2026 · 7 min read
ETFs & Index Funds

International Diversification: The Case Against Home Bias

Investors everywhere hold far more of their own country's shares than its size in global markets would suggest. The arguments on both sides of that habit deserve a fair hearing.

Sep 21, 2026 · 7 min read
ETFs & Index Funds

How to Build a Diversified Portfolio With Just Three Funds

You don't need dozens of holdings to be diversified. Here's how three low-cost index funds can cover almost the entire investable world.

Mar 11, 2026 · 6 min read
ETFs & Index Funds

The S&P 500 Explained: What It Is and Why It Matters

When people say "the market," they usually mean this one index. Here's how it's built, why it's weighted the way it is, and what it leaves out.

Mar 3, 2026 · 5 min read
ETFs & Index Funds

Index Funds vs. ETFs: What's the Real Difference?

They often track the exact same index and hold nearly identical portfolios — so what actually separates an index mutual fund from an index ETF?

Feb 23, 2026 · 5 min read
ETFs & Index Funds

What Is an ETF? A Complete Beginner's Guide

An ETF lets you buy hundreds of stocks or bonds in a single trade. Here's what's actually inside one, and how it differs from a mutual fund.

Feb 15, 2026 · 7 min read