Principles of Sound Investing: Why Consistency Beats Market Timing

Consistency is the least glamorous principle of investing and the one that does the most work. Staying invested through a downturn is not passivity. It is a decision, and for anyone with a meaningful portfolio, it is usually the highest-value decision you will make all year.

When you listen to financial news commentators, markets can feel capricious and arbitrary. Over the short term, that is fairly accurate. Over the long term, a handful of universal principles tend to govern results, and they guide every wealth management and investment decision we make at Intentional Wealth Partners.

The short answer

Investors who stay invested through volatility have historically captured returns that investors who move to cash do not. Over the 30 years from 1996 through 2025, an investor who missed just the 10 best days in the S&P 500 Index would have seen their return cut in half. Missing the 30 best days would have reduced the return by 84%. The best days cluster tightly around the worst ones, so exiting during a decline is the most reliable way to miss the recovery.

• 76% of the market's best days have occurred during a bear market or during the first two months of a bull market, according to Ned Davis Research, Morningstar, and Hartford Funds.
• Missing the 10 best days from 1996 to 2025 cut S&P 500 returns in half. Missing the best 30 days cut them by 84%.
• In 2024, the average equity investor trailed the S&P 500 by 848 basis points, the second-largest gap of the past decade, per DALBAR's 2026 Quantitative Analysis of Investor Behavior.
• The good days and the bad days arrive together. You cannot avoid one without risking the other.

Balance, consistency, and courage work together, and the overview of all three principles explains how. Each one provides a buffer from the constant drone of crisis and fear coming out of some news and media outlets. You can read about the other two in their own posts, courage and balance. Here, we start with consistency.

What consistency means once you already have assets

Early in your investing life, consistency mostly means contributing on a schedule. Once you have built real assets, it means something harder. It means leaving a seven-figure allocation alone during a quarter when your account statement is down more than you earned all year.

That is a genuinely different psychological task. A 20% decline on a $75,000 balance is uncomfortable. A 20% decline on a $1.2 million portfolio is $240,000, and it will feel like a reason to act. It usually is not.

I cannot tell you how many clients I have worked with over the years who kicked themselves for taking money out of the market at the wrong moment. If you have done it, you are not alone. The goal is to make sure it does not happen again.

Why the best days and the worst days travel together

Markets form patterns because there are humans in the driver's seat. Even trading models are built by people. Investors try to squeeze insights out of data and shape it into a story, often without any real causation behind it. No one has a crystal ball, but plenty of people act like they do.

That human behavior is exactly why the best days cluster during periods of maximum fear. Panic selling drives prices down fast, and the snapback is just as fast. Research from Ned Davis Research, Morningstar, and Hartford Funds found that 76% of the market's best days occurred either during a bear market or in the first two months of a new bull market. In other words, the days that produce most of the return arrive precisely when holding feels worst.

2025 was a clean illustration. The S&P 500 finished the year up 17.88%, but the single best day of the year landed in April, in the middle of the year's sharpest stretch of volatility. Investors who stepped aside during that stretch did not get a second chance at it.

It helps to remember what you actually own. Stocks represent partial ownership in real companies with real products, services, and profits. Over short periods, prices reflect sentiment, liquidity, and whatever is dominating the news cycle. Over long periods, they reflect what those businesses earn. Selling during a panic means trading a claim on real earnings for cash, based on how the last few weeks felt.

What inconsistency actually costs

The gap between what the market returned and what investors earned is where the cost shows up. DALBAR has measured this every year since 1985, and the pattern is consistent: the average investor trails the index, and the shortfall widens in volatile years.

In 2024, the average equity investor returned 848 basis points less than the S&P 500, the second-largest gap of the past decade. In 2025 the gap narrowed sharply, to 72 basis points, with the S&P 500 returning 17.88% against the average equity investor's 17.16%. That is one of the smallest gaps DALBAR has recorded since it began tracking in 1985.

The variability is the point. The gap is not a fixed tax. It opens up in exactly the years when staying put is hardest, which is why the behavior matters more than any single number. And even in the calmer year, investors were selling: DALBAR recorded equity withdrawals of 6.91% of assets in 2025, including a record monthly withdrawal rate of 2.30% in July.

Small annual shortfalls compound into large ones. As a hypothetical illustration, a $500,000 portfolio earning 9% a year for 20 years grows to roughly $2.8 million. At 8%, one percentage point less, it reaches about $2.33 million. A single point a year costs roughly $470,000 over two decades.

This illustration is hypothetical, does not represent any actual investment, and does not account for taxes, fees, or contributions. It is meant to show how a small annual gap compounds, not to project a result.

The tax bill nobody mentions when you go to cash

For investors with substantial taxable accounts, market timing carries a cost that the headlines never mention. Selling appreciated positions realizes capital gains. Depending on your income, that can mean 15% or 20% in federal long-term capital gains tax, plus the 3.8% net investment income tax, plus state tax.

So a defensive move out of the market is not free even when you are right about the direction. You may pay a six-figure tax bill for the privilege of being out, and then you have to be right a second time about when to get back in. Two correct calls in a row, with a tax drag in between. That is a demanding standard.

Consistency sidesteps the whole problem. It also preserves the step-up in basis for assets you intend to leave to heirs, which is a meaningful piece of the picture for families thinking about wealth transfer.

Consistency is not the same as doing nothing

This is the distinction that matters most for investors with complex portfolios, and it is where the principle gets misapplied. Consistency means holding to a strategy. It does not mean neglect.

A disciplined portfolio still gets attention. Rebalancing back to target when an asset class drifts outside its band is consistency in action, and it systematically sells what has run and buys what has lagged. Tax-loss harvesting during a decline turns volatility into a usable asset. Unwinding a concentrated position from equity compensation on a scheduled basis, rather than on a hunch about the stock, is the same principle applied to single-stock risk. So is adjusting your allocation because your time horizon or liquidity needs genuinely changed, which is different from adjusting because the news was bad.

The test is simple. Ask whether the change is driven by your plan or by the last two weeks of headlines. If you are working through a liquidity event, the same question applies. We wrote about that in the context of common mistakes to avoid when inheriting wealth and managing and investing a financial settlement after divorce.

Frequently asked questions

Does staying invested mean I should never sell anything?

No. It means selling should be driven by your plan rather than by market conditions. Rebalancing, harvesting losses, funding a known expense, and reducing a concentrated position are all legitimate reasons to sell. A scary headline is not.

What if I am close to retirement and cannot afford a big drawdown?

That is an allocation question, not a timing question. The answer is to build a portfolio whose risk level matches your horizon and cash flow needs before volatility arrives, often including a cash or short-bond reserve covering near-term withdrawals. Then you do not have to sell equities at a low to fund living expenses.

How much does missing just a few good days really matter?

More than most people expect, because the good days are concentrated. Over the 30 years from 1996 through 2025, missing only the 10 best days cut the S&P 500's return in half. Missing the 30 best days cut it by 84%. That is 30 days out of roughly 7,500 trading days.

Is it different when I have a large portfolio?

The principle is identical. The stakes and the friction are higher. Larger taxable balances mean larger realized gains when you sell, and larger dollar swings mean stronger emotional pressure to act. Both argue for more discipline, not less.

Can I just wait for things to settle down and then invest?

Markets rarely announce that they have settled down. By the time conditions feel calm, prices generally reflect it. Since roughly three quarters of the best days happen during bear markets or the earliest weeks of a recovery, waiting for calm means systematically missing them. If sitting out feels necessary, that is usually a sign the allocation is too aggressive for your actual risk tolerance, which is a fixable problem.

The bottom line

Historical performance does not guarantee future results, but historical perspective is genuinely useful in informing investment decisions. Patterns over long periods tell a clearer story than any given quarter does. Among the principles of sound investing, consistency is the one most closely tied to results, largely because it is the one investors abandon first.

You do not need to predict the best days. You need to be present for them.

Read the other two principles of sound investing, courage and balance, or start with the overview of how all three fit together.

Sources: Ned Davis Research, Morningstar, and Hartford Funds (data as of March 2026); DALBAR 2026 Quantitative Analysis of Investor Behavior. Index returns are for illustrative purposes only. Indices are unmanaged and not available for direct investment.

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