Breitburn Energy Partners LP has agreed to acquire QR Energy LP for $1.46 billion. The deal will create one of the largest U.S. oil producers structured as a master limited partnership. In recent years energy companies have preferred master limited partnerships because they pay no corporate taxes if they distribute most of their profits to investors, and investors love them because of the high yields. QR Energy's shares rose 10% to $20.85, while Breitburn's shares dropped 3%.