A lot happened in 2025. Markets swung wildly, the economy kept everyone guessing, and investors learned (or relearned) some valuable lessons about how this whole thing actually works.

While cataloging every major event would be exhausting, what matters more is extracting the investing wisdom that'll help us navigate future market moves and the news driving them. Here are eight lessons from the year that are worth carrying forward.

Bad Timing Can Still Work Out Fine

Picture this: You meet with your accountant in February, discover you have room to lower your taxable income, and decide to contribute more to your self-employed 401(k). Feeling productive, you transfer cash and buy into your S&P 500 index fund on February 18.

The very next day, the market tops out and proceeds to crash 20% before hitting bottom on April 8.

That's exactly what happened to award-winning author Sam Ro this year. Terrible timing, right? Except here's the thing: it didn't matter. The S&P 500 is now up 10% since that purchase. Sometimes the market rewards patience more than precision. You can be spectacularly wrong about timing and still come out ahead if you simply stay invested.

Corporate Disruption Is Accelerating

The S&P 500 experiences constant turnover as companies get dropped and replaced by up-and-comers. But that churn is happening faster than ever before.

In 1958, the average company stayed in the S&P 500 for 61 years. By the 1980s, that dropped to 30 years. By 2016, it was down to 24 years. By 2021, just 16 years. According to Bank of America research, roughly a third of the S&P 500 has been replaced since 2015 alone.

The reason? Disruptive companies are having downstream effects on incumbent businesses at an accelerating pace. BofA projects that if this trend continues, by 2027, companies could last just 12 years in the index before being disrupted out of existence. The corporate lifecycle is compressing dramatically.

Most Market Signals Aren't Actually Signals

Strategist bullishness? Market concentration? Dollar strength? Rate cuts? Price-earnings ratios? Last year's performance? None of these indicators consistently predict near-term market returns.

That's why analysts constantly use the phrase "ceteris paribus" in their research—Latin for "all else being equal." It's their way of acknowledging that markets are complex systems where isolated indicators rarely tell the whole story. What looks like a clear signal often turns out to be noise.

Holding Winners Is Psychologically Brutal

We talk constantly about how hard it is to pick outperforming stocks. But let's say you somehow managed to identify the winners. Problem solved, right? Not even close.

Morgan Stanley's Michael Mauboussin and Dan Callahan studied 6,500 stocks, including the 20 best performers over the 40-year period from 1985 to 2024. Even these ultimate winners put their investors through absolute torture.

The median maximum drawdown for the best-performing stocks was 72%. The median time from peak to trough was 2.9 years. The median time to return to the prior peak was 4.3 years. And that's assuming you somehow bought at the absolute bottom, which no one does.

After hitting bottom, these stocks generated median annualized abnormal returns of 8% over the next five years and 12% over the next decade. Great returns, sure, but you had to endure years of watching your portfolio get decimated to capture them. Identifying winners is hard. Actually holding them through the pain is a nightmare.

High Valuations Don't Always Mean Weak Returns

Valuations are currently hovering near five-year highs. Historically, when the stock market trades at above-average valuations, it tends to generate weak returns in subsequent years. But the key word is "tends"—it's not a rule.

Ten years ago, cyclically adjusted price-earnings ratios predicted low single-digit returns. Instead, the market delivered double-digit returns. Five years ago, the forward P/E ratio sat at a historically elevated 23.6x. The S&P 500 has nearly doubled since then.

Even sophisticated Wall Street research operations have consistently gotten this wrong. High valuations matter over very long time horizons, but they're surprisingly poor predictors of near-term performance. The market can stay expensive and keep climbing for years.

Markets Can Rally While the Economy Cools

The economy continued its years-long cooling trend in 2025. Meanwhile, the stock market rallied and now trades near record highs. This disconnect confuses people, but it illustrates an important truth: the stock market isn't the economy, and the economy isn't the stock market.

The market is forward-looking. It prices in expectations about the future, not current conditions. So while economic indicators might signal present weakness, stock prices can surge based on anticipated improvement down the road.

The economy may not be working for everyone right now, but it's working for stock market investors. Keep this in mind when you read news stories in 2026 about financial pain that some people are experiencing. Markets and main street don't always move together.

Earnings Drive Everything

Here's the simplest explanation for why stocks have roared higher this year: earnings. Earnings and expectations for earnings are the most important long-term drivers of stock prices. This isn't some esoteric theory—it's fundamental.

The connection between earnings growth and stock price appreciation was even highlighted in The New York Times' feature "14 Charts That Explain 2025." When companies make more money, their stock prices tend to go up. When earnings expectations rise, stock prices follow. It's that straightforward.

All the noise about tariffs, interest rates, political uncertainty, and market sentiment matters far less than this basic reality. Follow the earnings.

Good Years Tend to Be Great Years

The average annual return in the S&P 500 is about 10%. But here's the thing: average years are actually rare. The market almost never returns exactly 10%.

Instead, in positive years, the market typically returns around 20%. From this perspective, the impressive gains in 2023, 2024, and 2025 aren't particularly extraordinary—they're just what positive years tend to look like.

What does this mean for 2026? Nobody knows whether it'll be positive or negative, but we shouldn't expect it to be average. History suggests that's one of the least likely outcomes. Markets tend toward extremes more than midpoints.

So as we enter the new year, manage your expectations accordingly. The market will probably surprise us, one way or another. It usually does.