Activist investor Carl Icahn bought more Apple stock Tuesday as it plunged after an iPhone sales number that disappointed Wall Street.
Apple shares fell 7.2 percent in trading Tuesday morning. The stock actually lost some ground following Icahn's tweet. (What are Apple shares doing now? Click here)
Icahn told CNBC he has made "a great deal of money" over the years buying dips like Apple's on Tuesday.
"The long-term picture is completely unchanged," he said. "To me, it's even more compelling for Apple to buy back stock now," he added, saying he is encouraged by Apple CEO Tim Cook's comments on plans for new products.
Icahn also told Reuters that Apple's management "seems to be doing the right thing in running the business, but this is a financial issue,'' referring to the larger stock buyback. He said investors are underestimating Cook's message that Apple will introduce products in entirely new categories this year.
"I think it will be huger than people think,'' Icahn said. "They haven't done this in four years and the last one they did was something called the iPad, and let's not forget that Apple has a huge cult following.''
Last week, Icahn said he'd crossed the $3 billion mark on his Apple holdings and said he intended to keep buying.
He has been pushing the company to aggressively expand its stock repurchase and criticized the board last week for not doing so.
But not everyone is as sold on Apple's potential as Icahn, who has called his investment a "no brainer." The legendary Legg Mason investor Bill Miller took to Twitter himself Tuesday to respond.
—Reporting by CNBC's Scott Wapner and Reuters. Follow Scott on Twitter @ScottWapnerCNBC
This article has been updated to reflect Icahn's comments to Reuters.