Guide · Markets
IPO Book-Building Explained: Range, Demand, Final Price
Book-building is how banks set an IPO price: they publish a range, collect orders from investors, then price where demand is strongest. Anthropic set $70–$78 in November 2026.
On November 10, 2026, Anthropic filed an updated registration statement with the SEC that put a price range of $70 to $78 a share on its initial public offering of 825 million shares, with pricing expected on November 18 and Nasdaq trading the next day. That range is the visible part of a process called book-building, which is how almost every large IPO in the US is priced. Knowing how it works tells you what to read into the headlines between the range and the first trade.
Book-building starts with the roadshow. After the range is published, the company's managers and its underwriting banks spend a week or two presenting to fund managers. Investors respond with indications of interest: how many shares they would buy and, often, the highest price they would pay. The lead bank records every order in a single ledger, the book. None of these orders is binding until the deal is priced, which is why the book can grow, shrink or move up and down the range from day to day.
The price range is a starting point, not a promise. If orders far exceed the shares on offer, the deal is called oversubscribed, and the company can price at the top of the range, raise the range, or sell more shares. Weak demand leads to the reverse: pricing at the bottom, cutting the range or postponing. In Anthropic's case, CNBC reported that the book was already covered across the whole range, meaning orders at every price from $70 to $78 at least matched the shares on offer. That is a different statement from "oversubscribed many times", and the gap between the two is what the final price will reveal.
Pricing happens after the US market closes on the evening before trading starts. The banks then allocate shares, and here they have wide discretion. Long-term investors that placed early, detailed orders usually get more, while accounts suspected of buying only to flip on the first day get less. Retail investors usually receive 5% to 10% of a US IPO; Anthropic has targeted about 20%, according to CNBC. Most large deals also include an over-allotment option, often called the greenshoe, which lets the banks sell up to 15% more shares than planned and buy them back in the market if the price falls, a mechanism that supports the stock in its first weeks.
The first-day move is where book-building gets judged. A large jump means the shares were priced below what the market would pay, which is good for the investors who received allocations and costly for the company, which left money on the table. A flat or falling debut means the book was thinner than it looked, or that the price was pushed too high. Neither outcome says much about the company's value a year later. Two other dates matter more for supply: the end of the lock-up, usually 90 to 180 days after listing, when insiders can start selling, and the end of the analyst quiet period about 25 days after the IPO, when the underwriting banks begin publishing research.
For a trader following an IPO from the outside, the useful signals come in order. First, any change to the range or share count before pricing. Second, the final price against the range. Third, the opening print against the offer price, and whether the stock holds above the offer through the first week. Anthropic's deal will also test a structural detail: $26 billion of non-voting stock sold privately to seven strategic partners at the IPO price, outside the registered offering and outside the underwriters' lock-up, which adds a block of holders whose selling is not governed by the usual schedule.