Circle shares sank 4.9% in premarket trading on Wednesday, after the second-largest stablecoin issuer and a group of shareholders including co-founder and Chief Executive Officer Jeremy Allaire announced an offering to sell a combined 10 million shares.

Circle is offering 2 million shares while the selling shareholders are selling 8 million, according to a filing Tuesday with the US Securities and Exchange Commission. At the closing price on Tuesday of $163.21 each, the share sale would raise $1.63 billion.

The offering is set to price Thursday night, according to people familiar with the matter, who asked not to be identified as the information isn’t public. A representative for Circle didn’t immediately respond to a request for comment.

Circle went public in a June IPO that raised $1.2 billion, and has seen its stock price rise more than 426% through Tuesday’s close, after a stablecoin bill was signed into law.

The share sale comes within six months of the IPO, a period in which certain early shareholders typically are barred from selling their shares.

Shareholders can be released from the so-called lock-up agreements when the stock is up substantially from the IPO price and there is clear demand for the shares. Circle’s insiders had agreed not to sell before a few days after the release of the company’s September quarter results, or 180 days after the IPO, whichever came first, according to its earlier filings.

Three of Circle’s institutional backers before the IPO are the biggest sellers in the offering. IDG Capital is offering 1.17 million shares in the offering, General Catalyst is selling 1.12 million shares, and Fidelity Investments is offering 746,707 shares, the filing shows.

Allaire is selling 357,812 shares, and is expected to maintain 23.9% voting power after the offering, the filing shows.

The offering is being led by JPMorgan Chase & Co., Citigroup Inc. and Goldman Sachs Group Inc., the filing shows.