On March 12, 2020, I walked to work reading headlines about NYSE circuit breakers tripping at 7% daily drops. The Big Five Canadian banks fell 15% in a single day. Air Canada, the national airline, dropped 40% between open and close.

I’d been contributing to my portfolio automatically for years at that point. Steady amounts, every paycheque, into diversified ETFs. The kind of boring, consistent investing that every guide tells you to do. And then the world fell apart in a week and I had to decide: do I keep going, or do I stop?

I kept going. I even bought Air Canada on that 40% dip day. By end of day it had recovered to down 25%, so I was already up on the trade. But I won’t pretend it wasn’t terrifying. The question everyone fixates on is when to put your money in. Lump sum or a little at a time? But the bigger question, the one that actually determines your outcome, is whether you’ll stay in once you’re there.

This isn’t financial advice. What follows is based on my own experience and the research I’ve read. Past performance doesn’t guarantee future results. But the conversation around DCA versus lump sum is one worth having honestly, because the real answer is more nuanced than either side wants to admit.

What dollar-cost averaging actually means

Dollar-cost averaging is simple. Instead of investing a large amount all at once, you invest smaller, fixed amounts on a regular schedule. Maybe it’s $300 every two weeks when you get paid. Maybe it’s $1,000 on the first of every month. The key is consistency: same amount, same interval, regardless of what the market is doing.

When prices are high, your fixed amount buys fewer shares. When prices are low, it buys more. Over time, this smooths out your average cost per share. You never buy entirely at the peak, and you never buy entirely at the bottom. You land somewhere in the middle.

For most people, this is the default. If you’re investing from your paycheque, you’re already doing it. You don’t have a choice. The money shows up every two weeks, and you invest what you can. DCA isn’t really a “strategy” for these people. It’s just how life works.

What lump sum investing means

Lump sum investing is the opposite. You have a chunk of money available, and you invest all of it right away. Maybe you received an inheritance. Maybe you sold a property. Maybe you’ve been saving in a high-interest savings account for two years and you’re ready to move it into the market. Whatever the case, you take the full amount and put it to work immediately.

The argument for lump sum is straightforward: if the market goes up more often than it goes down (which it does, historically), then getting your money in as early as possible gives it the most time to grow. Every day your money sits on the sidelines, it’s missing out on potential gains.

What the research says

The most cited study on this comes from Vanguard. They compared the two approaches across multiple markets (U.S., U.K., and Australia) over rolling periods going back decades. The finding: lump sum investing beat dollar-cost averaging roughly two-thirds of the time. About 67% of the time, you’d have been better off investing everything on day one rather than spreading it out over 6 or 12 months.

The reason is exactly what you’d expect. Markets trend upward over long periods. If you spread your investment over 12 months, you’re keeping a portion of your money out of the market for up to a year. During that year, the market is more likely to go up than down. So by the time you invest your last instalment, prices are probably higher than when you started.

Here’s a simplified example to make it concrete:

Strategy	Amount invested	Approach	Outcome after 1 year (hypothetical)
Lump sum	$12,000	All invested on Jan 1	Full amount grows for 12 months
DCA	$12,000	$1,000/month for 12 months	Only the first $1,000 grows for 12 months. The last $1,000 grows for just 1 month.

In a year where the market returns 8%, the lump sum investor has all $12,000 compounding for the full year. The DCA investor has an average holding period of about 6.5 months. The math favours lump sum in any year the market finishes higher than where it started.

So why doesn’t everyone just invest lump sum?

Because the two-thirds stat, while true, hides something important.

First, most people don’t have a lump sum. The DCA-versus-lump-sum debate assumes you’re sitting on a pile of cash and choosing how to deploy it. But for the majority of Canadians, investing happens from regular income. You get paid, you set aside what you can, and you invest it. There’s no “lump sum” decision to make. The money doesn’t exist yet.

This is how I invested for years. I wasn’t strategically dollar-cost averaging. I was just investing what I had, when I had it. That’s not a strategy. That’s a paycheque.

Second, even when someone does have a lump sum, the psychology matters enormously. Imagine you inherit $50,000. You know the research says to invest it all today. But the market just hit an all-time high last week. The news is talking about interest rates. Your stomach tightens every time you think about clicking “buy” on a $50,000 order.

So you freeze. You tell yourself you’ll wait for a pullback. Weeks turn into months. The market keeps climbing. Now you feel like you missed it. So you keep waiting. A year later, the money is still in your savings account earning 3% while the market returned 12%.

This is the real risk. Not that DCA underperforms lump sum by a few percentage points. The real risk is that the pressure of a big, all-at-once decision causes you to invest nothing at all.

The worst outcome isn’t suboptimal timing

I’ve watched friends go through this exact cycle. They come into money, they research the “best” time to invest, they overthink it, and they end up on the sidelines for months or even years. They’re so afraid of buying at the wrong time that they never buy at all.

Here’s something the Vanguard study also showed: both strategies, DCA and lump sum, handily beat keeping money in cash. The gap between lump sum and DCA was relatively small. The gap between either strategy and doing nothing was massive.

Let me put that differently. If you have $20,000 to invest:

Approach	Expected outcome (based on historical averages)
Invest all $20,000 today	Best outcome roughly 67% of the time
Invest $5,000/month over 4 months	Slightly lower expected return, but still strong
Keep it in savings while “waiting for the right moment”	Almost certainly the worst outcome over any meaningful time horizon

The difference between the first two rows is small. The difference between either of them and the third row is enormous. The enemy isn’t DCA. The enemy is paralysis.

When DCA genuinely makes sense

Even if you accept that lump sum wins more often, there are good reasons to choose DCA deliberately.

You can’t stomach the volatility of a big single investment. If investing $40,000 all at once would keep you up at night, split it into four monthly chunks of $10,000. The slight statistical disadvantage is worth it if it means you actually follow through.

You’re entering the market for the first time. When everything is new, investing a large amount on day one can feel reckless. Spreading it out gives you time to get comfortable, to see how your portfolio moves, to build confidence. By the time your last instalment goes in, you’ve been through a few ups and downs and you understand how it feels.

You’re investing in something volatile. If you’re buying individual stocks rather than broad index funds, DCA smooths out the bumpier ride. A diversified ETF like XEQT already spreads your risk across thousands of companies. But a single stock can swing 20% in a month. Averaging in makes more sense when the underlying investment is less predictable.

You’re investing from income. Again, this isn’t really a choice. If your money comes in every two weeks, you invest every two weeks. This is DCA by default, and it works beautifully. You never have to think about whether “now” is the right time. You just invest and move on.

My own experience

I started investing in my early twenties, working a regular job, getting paid every two weeks. There was no lump sum decision to make. I’d set aside a portion of each paycheque and buy whatever I was investing in at the time, first mutual funds with Tangerine, then ETFs as I learned more.

Looking back, this was one of the best things about being a regular-income investor. I never had to agonize over timing. I never had to wonder if today was the right day to invest $30,000. I just invested what I could, consistently, for years. Some months the market was up. Some months it was down. I didn’t care because I knew the next contribution was coming in two weeks anyway.

The one time I did have a larger amount to invest, around $8,000 from a side project, I felt the exact tension I described above. The market felt “high.” I wanted to wait. I ended up splitting it into two chunks, a month apart. Did it matter? Probably not. But it got the money invested instead of sitting in my savings account while I waited for a dip that may or may not have come.

The pattern of advice keeps shifting

A few years ago, the prevailing wisdom was “just dollar-cost average and don’t think about it.” Before that, it was all about the Couch Potato portfolio. Now the pendulum has swung toward lump sum advocacy, with people citing the Vanguard study as gospel.

The truth is that both approaches work. The research favours lump sum slightly, and you should know that. But the research also assumes you’ll actually follow through, and that’s where DCA has an edge for a lot of people. The best investment strategy is one you can stick with. If DCA is what gets you invested and keeps you invested, it’s doing its job.

What actually matters, more than either approach, is staying in the market over time. The returns come from years of compounding, not from picking the perfect entry point.

Dollar-cost averaging vs. lump sum investing