Reading a 10-K in twenty minutes: the seven places changes actually show up

Every guide to reading a 10-K is written for somebody encountering a company for the first time. Start with the business description, they say. Understand how it makes money. Work through the financial statements. This is good advice, and it is advice for a task most investors perform rarely.

The common task — the one nobody writes guides for — is re-reading the annual report of a company you already own. You know how it makes money. You read the business description when you bought it. What you need to know is what is different this year, and roughly ninety per cent of the document is not.

That is a different reading problem. You are not reading for comprehension; you are reading for delta. Here is where the delta concentrates, in the order we check.

1. 01

   Item 1A — Risk factors

   The only place a company is required to write down what worries it. Look for additions, deletions, and modal-verb escalation: a risk that moves from "may adversely affect" to "has adversely affected" has changed category, not wording. Deletions are more informative than additions, because removing a risk factor is a small act of confidence that nobody forced the company to take.

2. 02

   Critical accounting estimates

   Where management tells you which numbers are judgments. A change in the inputs to an impairment test, a revision to a useful-life assumption, or a newly disclosed sensitivity are all signals that something in the underlying business moved enough to make the estimate uncomfortable.

3. 03

   Segment reporting

   Reorganised segments very frequently precede a change in what gets disclosed. Sometimes it genuinely reflects how the business is now run. Sometimes it means a line item that was becoming awkward is now inside a larger aggregate. Both are worth knowing; only one is worth worrying about.

4. 04

   Revenue disaggregation and concentration footnotes

   Customer concentration, geographic concentration, and the revenue recognition footnote. A single customer crossing the ten per cent disclosure threshold appears here first and usually appears nowhere else for another quarter.

5. 05

   Commitments, contingencies, and legal proceedings

   Read for what is newly specific. Litigation described in general terms for three years and suddenly accompanied by a range of reasonably possible loss has moved. So has a purchase commitment that acquires a hard number.

6. 06

   The auditor's report

   Critical audit matters tell you which parts of the accounts the auditor found hardest, in the auditor’s own words. A new CAM, a substantially rewritten one, or — loudest of all — a change of auditor between filings is worth stopping for.

7. 07

   Item 9A — Internal control over financial reporting

   Material weaknesses, significant deficiencies, and remediation language. The word to watch is "remediated" versus "remediation is ongoing"; the gap between them is often a full year and is rarely flagged anywhere else.

What you can safely skip

The business description, unless the company has made an acquisition or exited a segment. Properties. The market-for-registrant's-equity boilerplate. The exhibit index, unless you are specifically looking for a new material contract — in which case it is the fastest route to one.

The changes that are not changes

This is where a naive text diff fails, and it is most of the reason a raw diff of two 10-Ks is useless. A large majority of the textual difference between consecutive annual reports is:

• Date rolls and fiscal-year renumbering.
• Industry-wide boilerplate updates following new SEC guidance, where every issuer in a sector adds materially identical language in the same quarter.
• Counsel-driven rewrites that make a risk factor longer and more careful without changing what it says.
• Formatting and structural migrations, especially around inline XBRL tagging.

Distinguishing these from substantive edits is most of the work. It is also the specific thing we built Filing Diff to do — classification, not just detection.

Twenty minutes

Done in this order, with the prior year open alongside, a re-read of a company you already know takes about twenty minutes. Most of the time you will find nothing, which is the correct outcome and the reason almost nobody does it. The value is not in the average case. It is in the three or four times a decade when Item 1A quietly gains a paragraph about a customer you did not know was that important.