The filings a company makes, and what each one is for

A public company files constantly. Most of it is routine, and knowing which document carries which kind of information saves you from reading the wrong one.

Here is the working set.

The three that carry the business

10-K — the annual report. The full picture, once a year. Business description, risk factors, audited financial statements, management's discussion of results. Everything else on this list is either shorter than a 10-K or an update to one. If you are looking at a company for the first time, this is the document.

Deadlines run by company size. The largest filers have 60 days after their fiscal year ends; smaller ones get 75 or 90.

10-Q — the quarterly report. Three per year, for the first three quarters. The fourth quarter does not get its own 10-Q because the 10-K covers it. Financials are unaudited and the narrative is shorter. Risk factors usually appear only as changes from the annual filing, which makes them faster to read and often more informative than the full list.

Due 40 or 45 days after quarter end, again by filer size.

8-K — the current report. Filed when something material happens, rather than on a schedule. Executive departures, acquisitions, material agreements, bankruptcy, auditor changes, delisting notices. Earnings releases usually arrive as 8-Ks too.

Generally due within four business days of the event. The 8-K is where you find out that something happened; the next 10-Q or 10-K is where you find out what it did to the business. Those are different questions and they are answered in different documents, often months apart.

The one that is easy to miss

DEF 14A — the proxy statement. Filed ahead of the annual shareholder meeting. Executive compensation, board composition, related-party transactions, the matters being voted on.

This one matters because most large companies do not print Part III of the 10-K at all. They incorporate it by reference from the proxy. So if you open a 10-K and find that the governance section is four sentences pointing somewhere else, the proxy is where the content actually is.

Compensation structure is also the clearest available statement of what management is being paid to do, in a document that has to be specific about it.

Amendments

10-K/A, 10-Q/A, 8-K/A. An amendment to a filing already made.

The suffix is worth knowing because amendments are separate submissions with their own accession numbers. The original stays in the record. Nothing is edited in place.

Amendments range from trivial to serious. Many are administrative — an exhibit that was omitted, a signature page. Some are restatements. The form itself does not tell you which, and the number of amendments a company files is not by itself a signal of anything. What the amendment says is.

Registration and foreign issuers

S-1. The registration statement for a company going public. Long, unusually detailed about the business, and the only time many companies describe themselves at length without prior filings to refer back to. Useful reading well after the IPO.

20-F and 40-F. Annual reports for foreign private issuers. The 20-F plays the role a 10-K plays for a domestic filer; the 40-F is used by certain Canadian companies under a reciprocal arrangement. If you go looking for a 10-K for a company headquartered abroad and cannot find one, this is usually why.

What this means in practice

Three habits follow from the list.

If you want to know what a business is, read the 10-K. If you want to know what changed, read the most recent 10-Q against the one before it. If you want to know what management is paid for, read the proxy.

And if a number or a claim seems to come from nowhere, check whether an 8-K carried it first. A great deal of what gets discussed as news is an 8-K that most people reacted to without opening.