SAN FRANCISCO (AP) -- Activist investor Carl Icahn has sent a letter to Apple CEO Tim Cook three weeks after demanding the iPhone maker take steps to boost its stock price.

Icahn says in a post on his Twitter account that he sent the letter to Cook Wednesday afternoon. Icahn says he will share the letter Thursday on a new website called "Shareholders' Square Table."

The missive follows up on a Sept. 30 dinner with Cook that Icahn hosted at his New York apartment. During that get-together, Icahn said he lobbied Cook to spend $150 billion buying back Apple's own stock. That's more than double the amount that the Cupertino, Calif., company has committed to spend.

Icahn has said his fund has invested about $2 billion in Apple.

link