You have KRW 30 million available, but the fear of an immediate drop keeps your finger off the buy button. For money already assigned to long-term equity investing, gains missed while phasing it in are also a cost. If the first loss would make you abandon the plan, a short installment schedule with a fixed end date may be easier to carry out than waiting indefinitely.
In a public question posted on October 4, the author asked when to invest cash after selling a house he and his wife had bought. Receiving a large sum at once creates a different fear from investing each paycheck. This account is the author's self-report; the proposed allocation is not a reason to copy it with your own money. The original windfall-timing question
The decision concerns more than finding the bottom: how much cash waits, when purchases finish, and which equity allocation you can hold through the first fall. Compare immediate and phased investing with the same starting budget and the same final date.
Give the money a job before choosing its entry date
Our KRW 30 million is money assigned to long-term equities after setting aside living costs, emergency cash and near-term needs such as housing. This comparison does not decide whether an entire windfall needed soon should enter equities. Choose the use horizon and tolerable equity allocation first, then the entry schedule.
Someone investing KRW 1 million from each monthly paycheck cannot invest future pay today. Phasing an existing windfall deliberately keeps some available money in cash. Both can be called regular investing, but the available alternatives differ.
Why immediate investment more often finished ahead
Vanguard's February 2023 research: MSCI World 1976–2022, 100% equities, three equal monthly purchases, zero idle-cash interest, one-year wealth. Lump-sum outperformance was 68%, a historical frequency, not next year's odds.
When prices rise, more money exposed from the start earns more. Installments lower the purchase price only if later purchases actually occur at lower prices. Rising prices leave the cash buying fewer units. The number of purchases does not itself create a return.
Same KRW 30 million, different purchase sequences
We calculated three constructed price paths. The lump sum invests KRW 30 million at the start; installments invest KRW 10 million at the start, one month later and two months later. Both are valued 12 months from the start. A price of 100 is an arbitrary comparison level, not an ETF quote. Cash earns zero interest. Actual security performance, currency movements, taxes, fees and distributions are excluded.
| Constructed prices: start → month 1 → month 2 → month 12 | Lump-sum wealth at month 12 | Installment wealth at month 12 |
|---|---|---|
| Dip and recovery: 100 → 80 → 100 → 100 | KRW 30.00 m | KRW 32.50 m |
| Rise and reversal: 100 → 120 → 100 → 100 | KRW 30.00 m | About KRW 28.33 m |
| Continuing fall: 100 → 80 → 60 → 60 | KRW 18.00 m | KRW 23.50 m |
The second purchase on the recovery path occurs at 80. The final installment units equal KRW 10 m ÷ 100 + KRW 10 m ÷ 80 + KRW 10 m ÷ 100. Multiplying by the final price of 100 gives KRW 32.50 million. The price has returned to its starting level, but the extra units bought cheaply leave installments KRW 2.50 million ahead.
Reverse the sequence and the second purchase occurs at 120. Replacing 80 with 120 in the same formula produces about KRW 28.33 million, around KRW 1.67 million behind the lump sum despite the identical final price. These paths explain possibilities; they do not establish how often each occurs.
When a larger first loss would break the plan
After the first month on the dip-and-recovery path, lump-sum wealth is KRW 24 million. The first KRW 10 million installment is worth KRW 8 million, with KRW 20 million still in cash: KRW 28 million in total. The same price fall creates first losses of KRW 6 million and KRW 2 million because different amounts were exposed. That is the early shock installments reduce.
For USD 100,000 in 100% equities, the one-year medians were lump-sum USD 111,940/installments USD 109,580, and 5th-percentile values USD 82,947/USD 85,906. These are each strategy's distribution points, not matched-date loss savings. Original table: page 4
Do not stop at the strategy that won more often. For someone who would sell after losing KRW 6 million but could make the next scheduled purchase after losing KRW 2 million, the difference matters. Choosing installments need not imply knowing that a fall is coming; it can mean choosing a plan you can follow.
What if the waiting cash earns interest?
Crediting idle cash with the three-month US Treasury bill rate changed lump-sum outperformance to 65%, reducing the historical edge without reversing it. Interest comparison: page 5
Add an assumed 4% effective annual rate to our calculation. This is an input for sensitivity, not a current deposit quote. The monthly rate is the twelfth root of 1.04 minus 1. Initial cash of KRW 20 million earns a month of interest; after buying KRW 10 million, the balance earns another month's interest. At month 2, the last original KRW 10 million is invested. Accrued interest stays in cash and earns the same assumed rate until month 12.
The final interest cash is about KRW 101,697, not KRW 1.20 million obtained by multiplying the whole budget by 4%. The large principal waited only one or two months. Because interest is not used to buy equity, this sensitivity keeps a small cash balance after the final purchase.
Set both the initial and final price to 100, with both delayed purchases at the same price. The retained interest covers the reduced unit count until that later price reaches about 100.51. Above that price for both delayed buys, the lump sum finishes ahead. Under these assumptions, waiting interest cannot compensate for a large rise. An actual account needs its own interest rate, taxes and purchase costs.
Three purchases do not remove equity losses
If prices fall 100 → 80 → 60 and stay at 60, installment wealth finishes at KRW 23.50 million. That beats the lump sum's KRW 18 million but is still KRW 6.50 million below the starting budget. Losing less differs from protecting principal.
In the zero-interest baseline, the third purchase at month 2 puts all original principal into the same equity path. A further 20% fall from 60 to 48 would reduce the two balances by 20%, to KRW 14.40 million and KRW 18.80 million. Installments delay initial exposure. An excessive equity allocation still matters after purchases finish.
Choose a completion date before choosing a bottom
Write down when the money will be used and how much belongs in equities. If you can hold that allocation through losses, investing immediately reduces waiting cash. If the first fall would leave you entirely in cash or derail the plan, compare a short schedule with fixed amounts and an end date. Both decisions follow the allocation decision.
For three purchases, record the first, next and final purchase dates and each amount, rather than “when it gets cheaper.” For example, starting from an October 13 reference date gives November 13 and December 13 as the next reference dates, with a rule to use the next trading day if the market is closed. This is an example of a filled plan. The calculation above uses months 0,1,2,12 rather than actual calendar-day counts.
“Buy after a 1% fall from the high” has no completion date. A price that rises from 100 to 110 and then drops 1% is still 108.9. Waiting for a decline did not make it cheaper than today's 100. A fixed installment schedule and indefinite price waiting are different plans.
Before the first purchase, check the use horizon, total equity allocation, cash interest, currency conversion and trading costs. At the next purchase, check whether the use date or tolerable allocation has changed instead of inventing a fresh price prediction. At completion, review total equity exposure after cash has declined. A new emergency-cash need calls for changing the assigned amount first.
Invested fund money and new paychecks need different calculations
Selling a bank fund to buy another product involves more than the timing of uninvested cash. Compare redemption, conversion and repurchase costs, plus the change in asset exposure. Compare fund costs ahead with the costs of switching
For monthly gold or equity purchases from new pay, decide how much of each arriving contribution belongs in each asset. Separate that from the cost of waiting with an existing windfall, and examine holding risk after contributions. Compare a monthly gold budget, the spread and resale cash
Build the windfall plan in this order: how much to invest → when purchases finish → whether you can hold the resulting allocation through a fall. A plan that reaches the last purchase is more useful for your money than a promise to identify the bottom.