Warren Buffett passing on purchasing shares of Berkshire's stock when his company's cash pile is sitting at a record high ($325 billion) signifies that one of Wall Street's most ardent value investors is struggling to find a good deal. Berkshire's price-to-book value recently hit levels that haven't been consistently observed since 2008.

But Buffett hasn't lost his enamor with all stocks. The "Oracle of Omaha" has even invested $2.9 billion in one stock this year. What is it -- and is it a no-brainer buy now?

Stock-market investors are desperately trying to separate the signal from noise when it comes to Warren Buffett’s latest portfolio moves.