CLEVELAND (June 20)—M.A. Hanna Co. and the Geon Co. will be known as PolyOne Corp. after their proposed merger is completed in the third quarter, the companies announced. The combination would create a $3.5 billion polymer compounding and services company headquartered in the greater Cleveland area and would control an estimated 37 percent of the U.S. rubber compounding market and 40 percent of market for polyvinyl chloride compounding. It also would hold a leadership position in color and additive concentrates, specialty vinyl resins and engineered films. The deal still awaits regulatory and shareholder approval.