Some people are about to have the chance to get very rich.

Twitter, the microblogging service whose shares have more than doubled since its November initial public offering, will give insiders the first chance to sell their stock tomorrow.

No insiders sold in Twitter’s IPO, meaning none have been able to profit yet from the run-up in the stock price. Twitter, which debuted Nov. 6 at $26, closed at $56.47 at yesterday’s close in New York. They touched an intraday record of $74.73 on Dec. 26.

Twitter’s biggest shareholders include co-Founder Evan Williams, who has about a 10 percent stake, and Rizvi Traverse Management LLC, which along with its affiliates held an almost 16 percent stake after the IPO. Other shareholders include Benchmark Capital, Union Square Ventures, Spark Capital and celebrities such as Ashton Kutcher.

What happened to Facebook when their insider lockups expired?

In 2012, Facebook Inc.’s shares dropped to record lows amid the rival social network’s larger share-lockup expirations.