10-K vs 10-Q: What Is the Difference?

US public companies file two main periodic reports with the SEC. They cover the same kinds of information at different depth and frequency.

The short version

	10-K	10-Q
Covers	The full fiscal year	One quarter (plus year to date)
How often	Once a year	Three times a year (Q1, Q2, Q3)
Financial statements	Audited	Reviewed, not audited
Business description	Full: what the company does, competitors, employees	Not repeated
Risk factors	Complete list	Only changes since the 10-K
Length	Often 100+ pages	Usually 40-80 pages

Why there is no "fourth-quarter 10-Q"

The fourth quarter is not filed on its own. It is included in the 10-K, which covers all four quarters. If you want fourth-quarter figures alone, you take the full-year number and subtract the first three quarters, or use the earnings press release, where companies usually state the fourth quarter separately.

When they are filed

Deadlines depend on company size. Large and mid-size companies (accelerated filers) must file a 10-Q within 40 days of the quarter's end. The 10-K is due 60 days after year-end for the largest companies and 75 days for mid-size ones. The smallest companies get 45 days for a 10-Q and 90 days for a 10-K.

Which one should you read?

To understand what a company does and the risks it faces, start with the latest 10-K.
To see what changed recently, read the latest 10-Q.
For a headline first look, many people read the earnings press release, which arrives before the 10-Q and is not itself a filing that has been through the same review.

Related forms

A company also files an 8-K whenever something material happens, such as an earnings announcement, an acquisition, or a leadership change. Foreign companies listing in the US file different forms: a 20-F or 40-F instead of a 10-K, and a 6-K for interim news.

To read one, see how to read a 10-Q and where to find SEC filings.