Stock splits — methodology

How pre-split and post-split prices are computed

Both prices in the per-ticker table come from unadjusted end-of-day bars for the company's primary listing. Unadjusted means the historical record we store preserves the price as it was actually quoted on that date, before any retroactive split-adjustment math was applied.

• Pre-split price — the regular-session close on the most recent trading day strictly before the split calendar date.
• Post-split price — the regular-session open on the first trading day on or after the split calendar date.
• When we have no bar in the relevant window (the security was not yet trading, or the data feed has a gap), the cell renders as "—".

For very old splits (1960s–1970s) the unadjusted feed is sometimes sparse, especially around small stock-dividend events. We do not interpolate.

Cumulative multiple formula

This section covers the math only. For a friendly explanation of what each individual ratio means (forward, reverse, fractional stock dividends like 51:50, spin-off adjustments like Disney's 2000:1973), read the stock split ratios explained guide.

The cumulative multiple on a given row is the running product of all per-event multiples from the oldest split we store up to that row:

cumulativei = ∏j ≤ i ratioj

We deliberately stop the product at the oldest event on file. If the company executed splits or paid stock dividends before that date that we do not yet store, the bottom-row cumulative is a lower bound, not a definitive total.

Optional row context

Some split rows may show an info control next to the ratio. That copy is short editorial context from TickerLeague about why the ratio can look unusual—it is not a substitute for an official company filing and does not change the underlying math. The same text also appears in the collapsible "Row notes" block on the company stock-split history page when we have notes on file.

Data sources, freshness and limits

• Split events — sourced daily from a third-party corporate-actions feed, keyed by the official ex-date.
• Pre/post-split prices — sourced daily from unadjusted end-of-day bars for the company's primary instrument.
• The cumulative multiple is purely share-count math. It does not account for cash dividends, fractional-share cash-in-lieu payments or tax effects.

Related plain-English explainers

• Stock split ratios explained — every ratio family (forward, reverse, fractional dividend, spin-off).
• Cumulative split multiplier explained — how the running product is built and what it does and does not measure.
• Spin-offs explained — why ratios like 2000:1973 appear in the table.