Claman on Call: Icahn Talks Apple

The market pendulum swung again Thursday: U.S. stocks tanked erasing all of Wednesday's gains, as global growth worries jumped back on investors' radar. The Dow at one point fell 345 points, its steepest drop of the year, with Caterpillar and Goldman Sachs being some of the biggest decliners on the Dow today.

Carl Icahn is cooking up a storm with his open letter to Apple, urging company CEO Tim Cook to accelerate share buy back and calling Apple stock undervalued. The billionaire investor joined FOX Business on Thursday, along with his son Brett Icahn and Sargon Portfolio Manager David Schechter  -- all three signed the open letter to Cook -- and told FBN why they think the stock is worth double its current market value. And when FBN's Charlie Gasparino asked Icahn if he was buying  more Apple stock, he only replied he wouldn't say he was not buying shares right now.

Head to FOXBusiness.com/OnCall for more investing gems from the billionaire investor.

Wall Street's top Apple analyst Gene Munster of Piper Jaffray also joined FBN Thursday to weigh in on Icahn's position on Apple. Find out what subliminal message Munster believes he uncovered in the letter, plus whether he thinks you should buy the stock right now.

Also, Amazon is reportedly opening a brick-and-mortar right near Madison Square Garden -- in the heart of Manhattan. It's scheduled to open just in time for the holiday shopping season, according to the Wall Street Journal. FOX Business will be watching what Jeff Bezos is up to with this move.

Now, here's what you should be watching for on the last trading day of the week: Import prices at 8:30 a.m. ET, then at 9 a.m. ET we'll hear from Philadelphia Fed President Charles Plosser on monetary policy; followed by Kansas City Fed President Esther George's speech on the economy.

Be sure to check out all of today's interviews on FOXBusiness.com/OnCall and tune into Countdown to the Closing Bell every week day at 3 p.m. ET.