When a stock falls, many people think “let’s buy a bit more to lower the average cost”. Used well, averaging down can bring the break-even point closer; used badly, it ties up money in one stock and makes losses bigger. Let’s look at the effects and risks together, in numbers.
What averaging down actually changes
Averaging down changes two things.
- Your average cost falls. So even a small rebound makes it easier to get back to break-even.
- More of your money is in that stock. So if the price falls further, losses grow faster.
Some things don’t change. The loss already incurred up to the moment you average down stays the same. Your return percentage looks better with a lower average cost only because the denominator (the amount invested) got bigger.
The average-cost trap in numbers
You bought 10 shares at ₩70,000 (₩700,000) and the price fell to ₩55,000. Your current loss is ₩150,000 (−21.4%). Buying 10 more at ₩55,000 brings your average cost to ₩62,500.
| Later price | No averaging (10 shares) | Averaged down (20 shares) |
|---|---|---|
| ₩55,000 (unchanged) | −₩150,000 (−21.4%) | −₩150,000 (−12.0%) |
| ₩62,500 (rebound) | −₩75,000 (−10.7%) | ₩0 (break-even) |
| ₩70,000 (recovery) | ₩0 (break-even) | +₩150,000 (+12.0%) |
| ₩45,000 (further fall) | −₩250,000 (−35.7%) | −₩350,000 (−28.0%) |
If the price stays put, the loss is the same ₩150,000 but the return looks better, going from −21.4% to −12.0%. And if the price falls further, the return looks less bad but the actual loss is bigger. In the end, the outcome of averaging down depends on whether the price rises afterward.
Run the numbers for your own stock
Average cost calculatorA checklist before buying more
- Do you know why it fell? Separate a fall of the whole market from bad results or bad news specific to this company. If the problem is the company itself, a price that looks cheap can get cheaper.
- Is your original reason for buying still valid? If the earnings, growth and industry conditions you expected are intact, averaging down may be worth considering. If the reason is gone, cutting the position may make more sense than lowering the average cost.
- What would this stock’s weight be afterward? If one stock takes up too large a share of your total investment, that one stock ends up driving your whole account.
- Is the extra money truly spare? If you average down with living expenses, your emergency fund or money you’ll soon need, you may have to sell at a loss just when you need the cash.
- Do you have a next step? Unless you decide in advance what to do if it falls further after this purchase, and at what price you’ll cut your loss, you’ll keep buying on emotion.
How to plan staged buying
Most problems with averaging down come from doing it “without a plan”. If you plan to buy in stages from the first purchase, buying more after a fall becomes part of the plan rather than an emotional reaction.
Stage 1: buy ₩1 million at the current price
Stage 2: buy another ₩1 million if it falls 10% below the stage-1 price
Stage 3: buy the last ₩1 million if it falls 20% below the stage-1 price
Exit rule: close the position if it falls another 15% below the average cost after stage 3, or if the reason for buying disappears
If stage 1 was bought at ₩50,000, stage 2 is ₩45,000 and stage 3 is ₩40,000. Splitting the same amount of money buys more shares at lower prices, so the average cost after all three stages is about ₩44,628. Setting the numbers in advance like this lets you follow the plan without wavering in a falling market.
When to add to winners
Adding to a winner (pyramiding) means putting more money behind your original judgment when it proves right and the price is rising. Your average cost rises, but you increase the weight of a “winning stock” — the opposite of averaging down, which adds money to a losing one. Buying big near a peak can wipe out your gains in a small pullback, though, so it is also better to buy in stages.
Averaging down to avoid
- Averaging down with borrowed money: averaging down on margin or with unsettled buys can trigger forced selling by the broker for insufficient collateral if the price falls further. The loss is locked in at a price you didn’t choose.
- Endless averaging down: buying every time it falls, with no set number of times or amount, eventually puts most of your account into one stock.
- Averaging down to get back to even: averaging down with the thought “I’ll sell once I’m back to even” means your yardstick has become your purchase price rather than the company. The market doesn’t know your average cost.
This article explains general investing principles and does not recommend any particular stock or investment method. Responsibility for all investment decisions and their outcomes lies with the investor.