 NEW YORK--BUSINESS WIRE--Halper Sadeh LLP, a global investor rights law firm, is investigating whether the sale of Umpqua Holdings Corporation NASDAQ: UMPQ to Columbia Banking System, Inc. is fair to Umpqua shareholders. Under the terms of the agreement, Umpqua shareholders will receive 0.5958 of a share of Columbia stock for each Umpqua share they own. Upon completion of the transaction, Umpqua shareholders will own approximately 62 of the combined company. Halper Sadeh encourages Umpqua 