The following video is from Thursday's edition of Investor Beat, in which host Chris Hill and Motley Fool analysts Matt Koppenheffer and David Hanson dissect the hardest-hitting investing stories of the day.

Billionaire investor Carl Icahn has increased his stake in Apple by 22%, and has sent a letter to Apple CEO Tim Cook, continuing his push for a massive $150 billion stock buyback. Some have accused him of having purely short-term interests as the motivation behind the move, but he says that this couldn't be further from the truth. In the lead segment on today's Investor Beat, Matt and David discuss the feasibility of the buyback, how beneficial it would really be for the company, and what our analysts think of Icahn's real motivations.

Then, they take a look at four stocks making big moves today. Under Armour's profits jumped 27% and raised guidance for the full year, but overheated expectations caused the stock to fall in spite of the news. Ford beat expectations on profits again and raised guidance once more. Evercore Partners managed to more than double third-quarter profits, giving the stock its largest single-day pop all year. And AT&T was able to increase third-quarter profits and decrease the rate at which it was losing subscribers compared to its third quarter last year.

Finally, Matt and David tell investors why they'll be keeping an eye on shares of LifeLock and Greenlight Capital this week.

Chris Hill has no position in any stocks mentioned. David Hanson owns shares of Apple. Matt Koppenheffer owns shares of Apple and AT&T. The Motley Fool recommends and owns shares of Apple, Ford, and Under Armour. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.