---
title: "What Is an 8-K Filing? Material Corporate Events Explained"
description: "An 8-K is the SEC filing companies must submit within four business days of a major event: CEO departures, M&A, earnings, bankruptcies, cyber incidents. What the common item codes mean and how to read an 8-K next to insider trades."
canonical: https://insideralpha.ai/learn/what-is-a-form-8-k
date_published: 2026-07-21
date_updated: 2026-09-23
publisher: InsiderAlpha (https://insideralpha.ai)
---

Canonical URL: https://insideralpha.ai/learn/what-is-a-form-8-k
Published 2026-07-21. Updated 2026-09-23.

# What is an 8-K filing?

A **Form 8-K** ("current report") is how a U.S. public company tells the market that something material has happened, generally within **four business days** of the event. The 10-K and 10-Q arrive on a schedule. An 8-K arrives whenever an event triggers one.

## Common 8-K items and what they mean

- **Item 1.01** - Entry into a material agreement (contracts, partnerships, licensing deals).
- **Item 1.03** - **Bankruptcy** or receivership.
- **Item 2.01** - Completion of an acquisition or disposition.
- **Item 2.02** - **Earnings** (results of operations). Most earnings press releases arrive as an 8-K first.
- **Item 3.01** - Delisting notice from the exchange.
- **Item 5.02** - **Executive changes**: CEO and CFO departures, appointments, and board changes.
- **Item 7.01 / 8.01** - Regulation FD and "other events", the catch-alls for anything from clinical-trial results to contract wins.
- **Item 1.05** - Material **cybersecurity incidents** (required since December 2023).

That is the short list. For every item number, including rare ones like restatements (4.02) and changes in control (5.01), and counts of how often each appears, see [the full 8-K item reference](https://insideralpha.ai/learn/8-k-item-codes).

## Why traders read 8-Ks

An 8-K changes what the market knows about a company on the day it is filed. It can also supply the context a Form 4 leaves out: an executive-change 8-K after a [CEO purchase](https://insideralpha.ai/ceo-purchases), or a contract 8-K a few weeks after a [cluster buy](https://insideralpha.ai/learn/cluster-buying). InsiderAlpha lists each 8-K with a link to the original document and cross-references it against insider buying in the same company over the preceding six weeks - see [today's 8-K filings](https://insideralpha.ai/filings/8-k/today). Reading the filing is up to you. We point you to it and show who was buying beforehand.

## 8-K vs Form 4

The two filings answer different questions. [Form 4](https://insideralpha.ai/learn/sec-form-4) shows what insiders *did* with their own shares; the 8-K shows what the company says is happening. Read together, they tell you whether insiders were buying before an announcement. They do not tell you whether the insiders knew it was coming: a purchase ahead of good news can still be an ordinary open-window trade.

*This article is informational and is not investment advice.*