A subdivision (stock split) replaces each share with several cheaper ones. Par is divided by the same ratio; paid-up capital does not move. That is the clean test against a bonus: after a 4-for-1 split a £1 share becomes four 25p shares, and the company’s share capital figure is unchanged.
A consolidation is a reverse split. Several cheap shares become one dearer share, par rises, and paid-up capital is still the same. Issuers use it to lift a penny-stock price back onto a board’s minimum or to tidy a register after a collapse.
Both events are mandatory. Positions, open trades, and derivative contract sizes all have to be ratio-adjusted on the effective date.
Nippon Industrials KK (Tokyo, ISIN JP3899200005) is the split Atlantic Horizon UCITS ICAV already knows. Eighty thousand shares become 160,000 at half the yen price. There is no election, no cash, and no UCITS investment-policy question — only a position and price rewrite that Dublin has to have in the books before NAV is released. State Street’s Japanese sub-custodian will be long 160,000 whether Dublin posted or not.
Thames Industrial plc is the consolidation case. A 1-for-10 reverse split on a CREST line turns 100,000 1p shares into 10,000 10p shares. Fractions of a new share are usually sold and the cash sent to the holder. Tickets, stock-loan marks, and listed-option multipliers have to change on the same night or the books will show a quantity CREST no longer recognises.
The Irish administrator cannot outsource that overnight rewrite. Final NAV stays in Dublin, and the ICAV’s own shareholder register stays in Dublin. Custody can confirm Tokyo or CREST. It cannot sign the dealing price. The Cayman sleeve takes the same ratio on both names; it does not get a different mathematics, only a different valuation sign-off.
Neither event is meant to make the holder richer. The market price adjusts by the ratio. What changes is the unit the market trades, not the economic pie. Booking a split as income, or a consolidation as a disposal, is how a tax lot and a NAV tell different stories about the same night.