(Read more: Icahn has not taken stake in HP: Sources)
The company said the release was sparked by an April statement from the Securities and Exchange Commission that companies could use social media to communicate relevant information to shareholders and the public.
It is possible that the information that Mr. Icahn posts on Twitter (which may include information regarding companies in which we and/or Mr. Icahn have or may be contemplating an investment position) could be deemed to be material information. Therefore, in light of the SEC's guidance, we encourage investors, the media, and others interested in our company to review the information that Mr. Icahn posts on Twitter in addition to the information that we disclose using our investor relations website SEC filings, press releases, public conference calls and webcasts.
CNBC has learned, in fact, that Icahn plans a major announcement "in a matter of days."
Icahn has been in the news frequently lately.
He was in a very public—and likely losing—battle to wrest control of Dell and keep founder Michael Dell from taking the company private.
(Read more: Icahn rips Dell, says he can win fight)
He also has been staging a bitter war against fellow activist investor Bill Ackman at Pershing Square Capital. The two have sparred over Herbalife, waging a vicious argument on CNBC earlier this year. (Watch: Clash of the Titans: Ackman vs. Icahn)
At CNBC's Delivering Alpha conference in July, Icahn joked that it was his job to hand out discipline in the marketplace.
"It's a vicious cycle," he said. "The whole system is dysfunctional; that's why I make so much money."
—By CNBC's Jeff Cox. Follow him @JeffCoxCNBCcom on Twitter; CNBC's Scott Wapner contributed to this report.