The shamrock, not the four-leaf clover, is Saint Patrick's symbol of choice. A three leaf clover is pictured against black in this undated stock photo. Alamy — -- It’s officially March 17 ...

Ultramar Diamond Shamrock Corp. plans to repurchase $750 million, or 27%, of its common stock in a series of transactions expected to be completed within 3 months. Thereafter, it plans to buy back ...