This week
Your Mac's 19:00 notification and this page use the same rule (the lowest price since the start of last week). On Tuesday–Thursday your Mac shows a preview of next week, while this page keeps showing this week's amount until Friday's close. Buy each week through one of them only: pressing "I bought" here does not tell your Mac. Record each buy with "I bought it" so the weekly spread keeps track; typing a new amount of money waiting (for example after the dividend) restarts the spread from that amount — except in the last week before the dividend week, where the year's starting normal amount is kept.
What is left of a year's income after a year of spending goes into SPPW, spread weekly from the April dividend, growing at the chosen return above inflation. Moving these never changes this week's order above. A smooth average, not a forecast.
Grey = money you put in. Blue = growth on top (compounding). Dashed = goal. Inflation 2% a year (euro area), fund cost 0.12%; new money starts with the next April dividend and grows with inflation.
This page only covers SPPW. Your safety money (what is never invested, bills, the interest-rate check) is handled by the daily 19:00 notification on your Mac (uv run stocks plan).
Tested on 10-year periods of the MSCI World, the S&P 500 and the DAX, after XTB costs and tax, in today's euros: about 0.2–0.7% more after 10 years than the previous rule (roughly €2,000–9,000), and about 0.5–3% less than putting each dividend in at once (roughly €5,000–48,000) — the price of buying calmly. In every historical test there was a buy every week, and the biggest week was 5× a normal week; the previous rule could put the whole dividend in at once and then buy nothing for up to a year. It is not ahead every time: in the worst start tested (the DAX from October 2002) it ended 5% behind the previous rule.
How far these numbers go: daily prices of the MSCI World index (1985–2026, without dividends), an accumulating MSCI World ETF (2009–2026), the S&P 500 and the DAX, plus 4,000 simulated futures; the money waiting held in a money-market fund. Checked after the main study, not a forecast; a second reviewer reproduced every number.