Gemini, the digital-asset exchange run by the Winklevoss twins, is introducing a service that will allow investors to make big trades outside of the firm’s order books.

The service will allow traders to buy or sell large quantities of Bitcoins and other cryptocurrencies and will compete with companies that cater to large institutional traders. Block-trading companies have recently popped up in Hong Kong, Australia and other markets to meet demand from hedge funds and similar institutional buyers. One such service, Circle Trade, is already directly moving more than $2 billion a month in crypto assets.

Due to go live at 9:30 a.m. New York time on April 12, the Gemini Block Trading service will electronically broadcast orders to participating market makers simultaneously, the company said in a blog post Monday. Trade information will be published on Gemini’s market data feeds 10 minutes after the transactions are executed.

Exchanges that list contracts in a so-called central limit order book are useful for trades under certain sizes, which is determined by underlying demand -- whether for corn futures or IBM stock. Orders beyond those limits move the market in ways that hurt the trader or signal to others the direction prices are headed.

To avoid that, block trades are employed. A block trade’s size and price are negotiated privately off the exchange and then announced on the market in one fell swoop, often with a time delay to avoid triggering an outside price effect.

Cryptocurrency markets like Gemini, which typically use order-book trading, are joining equity and futures markets in offering blocks. Until recently, block trades have only been possible over the counter, through market makers or investors willing to take the risk of dealing outside an exchange.

This article was provided by Bloomberg News.