Anthropic plans unusual IPO lockup that lets some insiders sell early

Anthropic wants to rewrite one of the oldest rules in the IPO playbook.

The AI company behind the Claude models plans to let some early investors and employees sell shares before the standard 180-day lockup period ends. For a listing that could rank among the largest in history, that is a notable break from convention.

How the structure works

The plan has two moving parts, and they pull in opposite directions.

First, Anthropic plans to allow limited secondary sales by existing shareholders during the offering itself. A secondary sale means current holders sell their own stock to incoming investors, rather than the company issuing new shares to raise fresh capital.

Second, the remaining pre-IPO shares could face lockups longer than the usual 180 days. Under certain circumstances, those restrictions could stretch into mid-2027.

The company is also considering Rule 10b5-1 trading plans for employees. These are preset schedules that spell out future stock sales ahead of time, so selling runs on autopilot instead of reacting to the latest earnings call or market wobble.

The overall design is meant to prevent excessive selling pressure once the stock starts trading.

The road to the filing

Anthropic first submitted a confidential draft registration statement to the SEC on June 1, 2026. It then filed its S-1 registration statement on October 26, 2026.

A listing could arrive as soon as mid-November.

Valuation discussions for the IPO are centered on a range of $1.5–2 trillion, depending on market conditions.

Revenue is a big part of that pitch. Anthropic has reported rapid growth, with quarterly figures projected in the mid-teens of billions by Q3 2026.

The lockup plan also stands apart from some of the other high-profile offerings in the current cycle. SpaceX and Cerebras did not permit secondary sales in their IPOs, keeping existing holders out of the offering entirely.

What this means

For employees, the appeal is obvious. Workers at private tech companies often hold much of their compensation in stock they cannot easily sell, and an early window offers a chance to turn paper value into money they can actually spend.

The flip side is that secondary sales send proceeds to the sellers, not to Anthropic’s balance sheet.

Several details will be worth watching as the process moves forward. Those include how large the secondary allocation ends up being, which shareholders qualify, and exactly which circumstances would extend lockups into mid-2027.

A mid-November listing would put the offering into the market quickly after the October 26 filing. Where Anthropic lands within, or outside, the $1.5–2 trillion range discussed will shape how the rest of the AI sector gets valued.