Carl Icahn readies a major Twitter surprise

Carl Icahn, the 77-year-old billionaire investor whose stock ideas move markets, is about to take to Twitter in a big way.

Icahn, whose Twitter handle is @Carl_C_Icahn, will reveal his next big investment idea on the social network, according to CNBC contributor Karen Finerman, a hedge fund manager and acquaintance of the investor who spoke to him via phone today.

The timing of the idea reveal is uncertain, according to their conversation. But Icahn did say it would be presented like a "treasure hunt" with clues given first, according to Finerman.

Icahn did not immediately return a call for comment.

The use of Twitter by the legendary investor would be a giant step forward for the seven year-old social platform, which has gained a big following by the investment community, but has yet to be used by someone of this stature to reveal a stock pick.

Icahn joined Twitter a little over a month ago, but has used it mostly to link to articles, wish a happy Fourth of July and promote his appearance at CNBC's Delivering Alpha Conference.

(Read more: Icahn at Delivering Alpha)

Most big name investors such as Warren Buffett, David Einhorn, Leon Cooperman and Daniel Loeb reveal their new ideas in filings or at expensive investment conferences.

Warren Buffett made a big splash about three months ago when he joined Twitter under the handle @WarrenBuffett, but has only tweeted three times since then.

Social platforms are already moving markets these days, prompting an April announcement by the SEC allowing companies to announce non-public information through social media in compliance with Regulation Fair Disclosure.

The most infamous cases that drove the SEC's decision were Tesla Chief Executive Elon Musk's (@elonmusk) tweet last December that the company was cash flow positive during a certain week in November, and Netflix CEO Reed Hasting's Facebook post last July discussing the one billion video hours viewed by subscribers during the previous month.

Many Wall Street firms still do not allow their employees to access Twitter on their work computers, leading many to try to follow on their phones and risk getting in trouble with compliance officers.

They may want to change that policy soon because one of the richest men on Wall Street is about to rock the social world.

— Additional reporting by Maxwell Meyers