Activist investor Carl Icahn has just tweeted that his investment firm has acquired an additional $500 million in Apple stock over the past two weeks, pushing his stake to over $3 billion. Calling continued investment in Apple a "no brainer" at current prices, Icahn also continues to believe that Apple needs to significantly increase its stock buyback program. A more in-depth letter from Icahn on the topic will be forthcoming. Having purchased $500 million more $AAPL shares in the last
