	oppenheimer ups viacom via stake to pct oppenheimer and co a new york brokerage firm said it raised its stake in viacom international inc to the equivalent of shares or pct of the total from shares or pct in a filing with the securities and exchange commission oppenheimer said it bought a net viacom common shares between jan and march at prices ranging from to an average of dlrs each part of its stake is in options it said it bought the shares as part of its arbitrage and investment business movie theater magnate sumner redstone and a viacom management group are in a bidding war for viacom reuter 
