SECURITY PACIFIC <SPC> BUYS ORBANCO <ORBN> Security Pacific Corp said it completed its previously announced acquisition of Orbanco Financial Services Corp after receiving federal approval of the deal. Security Pacific said the Federal Reserve Board approved on Wednesday its purchase of the Portland, Ore.-based bank holding company and financial services concern. The purchase of Orbanco, for about 47 mln dlrs in cash and common stock, will be effective in 30 days, a Security Pacific spokeswoman said. Terms call for each share of Orbanco common stock to be exchanged for about 14 dlrs of Security Pacific common stock, plus 1.50 dlrs cash. Each share of Orbanco's 100-dlr par value preferred stock will be exchanged for 100 dlrs cash, plus accrued dividends. Orbanco, with one billion dlrs in assests, is the holding company for the Oregon Bank, Orbanco Real Estate Service Co, American Data Service Inc and Orbanco Securities Corp. Security Pacific now has four major regional bank purchases outside California completed or pending. Security Pacific bought The Arizona Bank, with assets of four billion dlrs, in the fourth quarter of 1986. Pending approval currently is the purchase of Rainier Bancorporation <RBAN>, with assets of 9.2 billion dlrs. In anticipation of legislative changes that take effect in 1989, Security Pacific has also negotiated the future purchase of The Nevada Bank, with assets of 615 mln dlrs. Security Pacific is the sixth largest U.S. bank holding company, with assets of about 61.60 billion dlrs.