How to
How to check what was true about a company on a past date
First, which date do you mean
A fact about a company has three dates, and they are often weeks apart:
- The day it took effect: the new CEO's first day, or the last day of the quarter a revenue figure covers.
- The day it was published: the filing or announcement that made it public. A quarter's revenue is filed weeks after the quarter ends.
- The day your source recorded it, which can be much later.
"Who was the CEO on 1 March" asks about the first. "What did the market know on 1 March" asks about the second. Decide which before you search, because the answers can differ.
US public companies: SEC EDGAR
EDGAR holds what companies file with the SEC, free to read, and every filing carries its filing date.
- Find the company in EDGAR company search and note its CIK number.
- For a change of CEO or another officer, look at Form 8-K filings with Item 5.02 (departure or appointment of principal officers). A company must file within four business days of the event. The latest Item 5.02 filing before your date names who held the role.
- For revenue and other figures, open the Form 10-K (annual) or Form 10-Q (quarterly) for the period. To see what had been reported by your date, take the latest one filed on or before it.
- Limit the results by form type and date. Full-text search covers filings since 2001 and takes a custom date range.
- For data rather than documents, the API needs no key: https://data.sec.gov/submissions/CIK##########.json lists a company's filings and https://data.sec.gov/api/xbrl/companyfacts/CIK##########.json returns its tagged figures, with the CIK padded to ten digits. Declare a User-Agent that names you, and stay under 10 requests a second.
Limits: EDGAR covers only companies that file with the SEC, and tagged figures begin in 2009.
UK companies: Companies House
The Companies House register is free to search without an account.
- Search for the company on Find and update company information.
- Open People. Each officer is listed with an "Appointed on" date, and former officers with a "Resigned on" date, so you can read off who held office on your day.
- Open Filing history for each document with its filing date and a link to the filed PDF.
Limits: the register shows what the company filed. Companies House states on these pages that it does not check the accuracy of the information filed. Other fields show the current value.
What a website said: the Wayback Machine
The Wayback Machine keeps copies of public web pages by the day they were captured. It is the way to see what a company's leadership or about page said at the time.
- Enter the page's address at web.archive.org and choose Browse History.
- Pick the capture nearest your date on the calendar.
- To do the same from a script, ask http://archive.org/wayback/available?url=example.com×tamp=20240301 for the capture closest to a date.
Limits: a capture shows what the page said on that day, not when the fact began, and a page can be out of date when it is captured. Pages behind a login, and pages whose owners excluded them, are not archived.
A quick check: Wikidata
A Wikidata statement can carry a start time and an end time, so a company's item may list each chief executive with the years they served, and may keep older values beside the current one.
Limits: the dates are there only where an editor added them, and a reference is expected but not required for each statement. Open the statement's reference before relying on it.
Any day, asked directly: AsOf
AsOf stores each fact as a claim with the day it took effect, the day it ended and the sources that state it, drawn from the filings and official announcements above. A replaced value is kept, so any day can be asked for directly.
- Ask in words: search "who ran Nvidia in 2019" or "Meta revenue as of 2024-06-30" on asof.is.
- Or open a company's record for a day: https://asof.is/record/openai?as_of=2023-11-18.
- From code, GET https://asof.is/v1/entities/openai?as_of=2023-11-18. Add known_by=YYYY-MM-DD to count only what had been published by that day.
- Inside Claude, add the AsOf connector and ask the question; the answer names its source and its as-of date.
Limits: the record covers tech and AI companies and a set of other public companies, not every company. When it holds nothing for a day it says why (not covered, not yet checked, or nothing held then) and does not guess.
Which source for which question
| Question | Start with | Then confirm with |
|---|---|---|
| Who was the CEO of a US public company on a date | AsOf, or EDGAR Form 8-K Item 5.02 | The 8-K itself |
| Who was a director of a UK company on a date | Companies House, People | The filed appointment or termination |
| What revenue had a US public company reported by a date | EDGAR 10-K and 10-Q, by filing date; or AsOf with known_by | The filing |
| What a company's website said on a date | Wayback Machine | A second capture near the date |
| What changed at a tech company between two dates | AsOf | The sources each claim links |
| A private company outside tech with no filings | A company register, then a web archive | A dated announcement |
Questions
How do I find out who was CEO of a company on a specific date?
For a US public company, find the latest Form 8-K with Item 5.02 filed before that date on SEC EDGAR; it names the officer who was appointed or who left. For a UK company, the Companies House People page lists each officer's appointed and resigned dates. For tech and AI companies, AsOf answers the question directly for any day, with the source.
How do I find what revenue a company had reported at the time?
Take the latest annual (10-K) or quarterly (10-Q) report filed on or before your date on SEC EDGAR. A figure for a period is filed weeks after the period ends, so the filing date, not the period end, tells you what was known. AsOf's known_by parameter applies the same rule.
Can the Wayback Machine show what was true on a date?
It shows what a web page said on the day it was captured. That is evidence of what a company published, but a page can be stale when captured, and it does not say when a fact began or ended.
What does "as of" a date mean for a company fact?
It means the value that held on that day: the person in the role, or the latest figure for a period that had ended. It is different from what had been published by that day, which depends on when the filing or announcement came out.