 NEW YORK--BUSINESS WIRE--Halper Sadeh LLP, a global investor rights law firm, is investigating whether the sale of Great Western Bancorp, Inc. NYSE: GWB to First Interstate BancSystem, Inc. is fair to Great Western shareholders. Under the terms of the agreement, Great Western shareholders will receive 0.8425 shares of First Interstate Class A common stock for each Great Western share they own. Following completion of the transaction, Great Western shareholders will collectively own 43 of t 