It's that time of year. Big names of the financial world including David Einhorn, Whitney Tilson, Dan Loeb, and T. Boone Pickens are at the Robin Hood Investor's Conference in New York, and they're presenting some of their best long and short ideas.

Pfizer Inc. is in advanced talks to buy Allergan Plc for as much as $380 per share, according to people familiar with the matter, valuing the Botox maker at as high as $150 billion -- if the U.S. government doesn’t get in the way of the drug industry’s largest-ever deal.

When Concordia Healthcare Corp. agreed to issue a 14 percent stake to a private equity firm, the Canadian drug manufacturer tucked into the deal several layers of protection from shareholder activists.

Allergan Plc, the Ireland-based drugmaker in talks to be taken over by Pfizer Inc., dropped in late trading on plans by the U.S. Treasury Department to deter companies from doing deals to move their headquarters abroad for tax purposes.

U.S. stocks were little changed as a retreat in energy shares offset higher-than-forecast earnings from Home Depot Inc. and Wal-Mart Stores Inc., while firming inflation bolstered speculation the Federal Reserve will raise interest rates next month.

With most products, you’d expect a flood of new supply to quickly drive back down a price spike caused by a temporary shortage. Not so in the topsy-turvy world of hospital pharmaceuticals.