10-K vs 10-Q vs 8-K: What's the Difference?
If you spend any time reading about public companies you will keep running into three filing names: 10-K, 10-Q, and 8-K. They sound like model numbers for a printer. They are actually three different kinds of mandatory SEC filings, each with a different job.
Here is how I keep them straight.
10-K: the yearly deep dive
The 10-K is the annual report. One per fiscal year, filed within 60 to 90 days after the fiscal year ends depending on the size of the company.
It is the longest of the three (often 100 to 300 pages), and the most comprehensive. Audited financial statements, a full business description, risk factors, management commentary, executive compensation, legal proceedings. If you only read one filing per year for a company you own, read this one.
A 10-K is audited. That is an important detail. An independent accounting firm signs off on the numbers. The 10-Q does not get that level of scrutiny.
10-Q: the quarterly check-in
Public companies have to file a 10-Q after the first three quarters of their fiscal year. (The fourth quarter is covered by the 10-K, so there is no Q4 10-Q.)
A 10-Q is shorter than a 10-K, usually 30 to 60 pages. It is unaudited, which is why it comes out faster. The focus is on the quarter that just ended: income statement, balance sheet, cash flow, and a shorter MD&A section explaining what moved.
Most of the earnings-season drama you see in the news is tied to 10-Q filings (and the accompanying 8-K press release, more on that in a second). When someone says "Apple's quarterly earnings came in above expectations," the official numbers behind that headline live in the 10-Q.
8-K: the breaking news form
An 8-K is not scheduled. A company files one whenever something material happens that investors ought to know about before the next regular filing. "Material" is doing a lot of work in that sentence, but the common triggers are:
- Earnings announcements (yes, the press release with the quarterly numbers is an 8-K)
- Changes in leadership (CEO, CFO, board)
- Mergers or acquisitions
- Going into bankruptcy or out of it
- Major contract wins or losses
- Departure of an auditor
A company has four business days to file an 8-K after the triggering event. Because of that tight window, 8-Ks are short and to the point. The substance is usually in exhibits attached to the filing.
If you want to know what a company has been up to between quarterly reports, the 8-K list is where you look.
Quick comparison
| Filing | Frequency | Length | Audited? | What it's for |
|---|---|---|---|---|
| 10-K | Once a year | Long | Yes | Full annual picture |
| 10-Q | Three times a year | Medium | No | Quarterly update |
| 8-K | As needed | Short | No | Material events |
Which one should you actually read?
Depends on what you want to know.
- "Is this company worth owning?" Start with the 10-K. It gives you the business model, risk factors, and audited financials in one document.
- "How did last quarter go?" Read the most recent 10-Q, and the 8-K earnings release that came out alongside it. The 8-K usually has the press release and slides; the 10-Q has the detailed statements.
- "What's been going on lately?" Scan the recent 8-Ks. It is the fastest way to see news that matters.
Every one of these filings is free on EDGAR. EarningsLens pulls them in automatically and runs an AI summary over each one, so you can get the gist in a minute or two before deciding whether to read the full document. You can try it on any S&P 500 stock.
One last thing worth knowing: filings are the source of truth, but they are not the whole story. A company can be in compliance with every SEC rule and still be a bad investment. The filings tell you what happened. Whether the business is actually good, and whether the stock is worth owning at today's price, is on you.