[OTVVp.VI] VIENNA, Dec 10 (Reuters) - Austria's partially state-owned Volksbanken AG <OTVVp.VI> offered on Monday to buy back hybrid notes due in 2016 as a way to improve its capital structure. The bank issued a nominal 300 million euros worth of the subordinated lower tier II notes and has offered to buy them back at 75 percent of face value, it said in a statement.