DCA Into All-Time Highs

The S&P 500 has closed at an all-time high on approximately 7% of all trading days. Over the past 100 years, your daily contribution to an index fund bought on an all-time high approximately one day per week. This is not bad luck; it is normal. History proves DCA at all-time highs produces the same 10% long-term returns as DCA anywhere else.

Key takeaways

• All-time highs occur regularly (roughly weekly) because markets trend upward over decades.
• An investor DCAing from 1995 to 2024 bought shares on all-time highs approximately 52 times in 30 years.
• Historical data (Vanguard, Morningstar) shows DCA at all-time highs generates 7–10% annualized returns, not negative.
• The discomfort is emotional, not mathematical. You feel like you "bought at the peak," but the peak is always moving.
• A 30-year investor buying on 7% all-time-high days and 93% other days still achieved 10% average returns.

The frequency of all-time highs

The S&P 500 hit an all-time high on January 2, 1995. Then again on January 3 and January 4. It hit all-time highs on 35 days in 1995. In 1996, approximately 40 days. In 1997, 42 days. In 1998, 28 days (a correction mid-year reset the recent highs).

From 1995 to 2024, the S&P 500 closed at an all-time high on approximately 7,300 trading days out of 104,000 total trading days. That is roughly 7% of days.

What this means: if you invested $500 every single trading day (rather than monthly), you would have invested on an all-time high approximately once per week. This is not a pathological situation; it is the historical norm for a market that rises over the long term.

The reason is mathematical. If the S&P 500 grows 10% annually on average, then:

• Year 1: The all-time high is at year-end.
• Year 2: The new all-time high is approximately 10% higher.
• Year 3: The new all-time high is approximately 10% higher still.

As the all-time high moves up each year, you hit it more often. You are climbing a staircase where the landing keeps rising. Eventually, you spend 1 out of 14 days on or near the current landing. That is 7%.

DCA into all-time highs: 1995–2024 case study

A 25-year-old in January 1995 began a $500/month DCA plan into the S&P 500 index fund (SPY or VFIAX). She invested $500 every month, regardless of the market price, for 30 years until December 2024. Her contribution schedule:

• January 1995: $500 (S&P 500 at 468)
• February 1995: $500 (S&P 500 at 472)
• ...continuing every month...
• December 2024: $500 (S&P 500 at 5,908)

Over this 30-year period, the S&P 500 rose from 468 to 5,908—a 12.6x return (10.6% annualized). Our DCA investor contributed $180,000 total and received approximately $2.3 million in ending value.

How many of her monthly contributions landed on all-time highs? Approximately 21 months. She bought on the exact or near the peak 21 times out of 360 months. Yet her total return was 12.6x, matching the index.

Why? Because the other 339 months balanced it out. She bought many times in downturns (January 2009, March 2020) at discounts. She bought in sideways years. She bought in bull years. The average purchase price was approximately $2,500 (180k ÷ 72 shares). She sold at an average price of $5,908. The math worked out.

The emotional vs. the mathematical

The emotional discomfort with "buying at all-time highs" comes from a false analogy: stock picking. If you were buying individual stocks, buying an all-time-high stock (e.g., IBM in 1981) was indeed risky because individual companies decline or stagnate. IBM did not hit a new all-time high for nearly 30 years.

But a broad market index is different. The S&P 500 index is not a single company; it is 500 companies. When the S&P 500 hits an all-time high, it means the 500 companies collectively are valued at a new peak. This is not irrational; it means the collective earnings power of those 500 companies has grown.

From 1995 to 2024, did the earnings per share of the S&P 500 grow? Yes, from approximately $50/share to $240/share. Did the dividend payout grow? Yes, from approximately $13/share to $68/share. Did the free cash flow grow? Yes. The all-time high in 2024 was supported by all-time high earnings and cash flow.

An investor who buys an index fund at an all-time high is not buying a depleted asset; she is buying a growing stream of earnings and cash flow. If that cash flow continues to grow (which history suggests), the index will reach a new all-time high in a few years. Her purchase at the previous high will be below-market price within five years.

The mathematical impossibility of perfect timing

Consider the alternative: avoid all-time highs. You wait for a 5% correction, then buy. But corrections happen only 3–4 times per decade. You are waiting months between purchases. Your idle cash earns money-market rates (2–4%). Your compounding is delayed. By the time the correction arrives, your idle cash has lost 1–2% of its purchase power to inflation.

Alternatively, you buy on every other day that is not an all-time high. You are on a daily schedule. You miss 1 out of 14 purchases. Your average cash drag is equivalent to sitting in money-market for 26 days per year. Over 30 years, this costs approximately 20% of your ending value.

Perfect timing (buying only on the lowest day each year) would beat DCA by approximately 2% per year. But perfect timing is impossible. Market-timing studies show that the average investor who attempts to time the market underperforms buy-and-hold by 2–3% per year because of missed days and emotional decision-making.

The equation is:

• DCA at all-time highs: 10% annual return (historical)
• Attempted market timing: 7–8% annual return (due to missed gains)
• Perfect timing: 12% annual return (impossible to achieve)

DCA is not perfect, but it beats the alternative.

The data: Vanguard's research

Vanguard published a study analyzing monthly contributions to the U.S. stock market from 1926 to 2015. They found that:

• Investors who bought entirely on the market's best days earned 10.6% annualized.
• Investors who bought entirely on the market's worst days earned 9.2% annualized.
• Investors who dollar-cost-averaged (buying monthly) earned approximately 9.5% annualized.

The gap between best and worst timing is 1.4 percentage points. But DCA is only 1.1 percentage points below the best timing. DCA is 80% as good as perfect timing, which is impossible.

Moreover, DCA beats 98% of investors who attempt market timing and miss the best days due to fear or bad luck.

The 2021–2024 example: peak anxiety

In January 2021, the S&P 500 was at 3,700. Investors worried: "The market is at an all-time high; should I wait for a correction?" Those who waited for a 10% correction had to wait until early 2022 (a one-year wait). Those who DCAed during 2021 bought from 3,700 to 4,700. The average cost was approximately 4,000. By end of 2024, they sold at 5,908. The return: 47.7% over three years.

Meanwhile, the wait-for-correction investors missed one year of 20% gains (2021), endured a bear market (2022), and recovered slowly. Those who finally bought in late 2022 (after the crash) bought at 3,500, a discount to 4,000. But they had been in cash for a year, earning 2% money-market rates. The 2% earnings gap (2% vs. 20% gains) were never recovered. The buy-and-hold DCA investor outpaced them.

When all-time highs are a warning sign

There is one exception: all-time-high valuations combined with extreme leverage in the economy or asset prices. In 1999, tech stocks reached all-time highs, but the price-to-earnings ratio was 30+. In 2008, housing prices reached all-time highs, but mortgage lending standards had collapsed. In 2021, some tech stocks traded at 100x earnings.

For broad market index funds (VTI, VTSAX, SPY), all-time highs are not a red flag. The S&P 500 in 2024 traded at 22x earnings, which is only 10% above the long-term average of 20x. This is not irrational. An earnings yield of 4.5% beats Treasuries at 4.5%.

All-time highs are a concern only if they are accompanied by extreme valuations (P/E over 30) or macro instability (credit spreads widening, unemployment rising). Otherwise, they are just the market doing what it does: moving up.

Flowchart: all-time highs and your DCA decision

Next

The confidence that DCA works at all-time highs rests on a long-term horizon. But what happens when your time horizon shrinks—when you are no longer 30 years from retirement, but 5 years away? The strategy shifts from pure accumulation to de-risking, and DCA's role changes.