The market for Korean art outside of South Korea is smaller than within the country. Only a few auction houses regularly hold sales and other than stellar pieces of ceramics or paintings, prices are extremely low. Auction houses most often include a Korean art section within sales of Japanese arts, for example Bonhams and Christie's. iGavel also occasionally holds sales. An alternative might be to contact the Overseas Korean Cultural Heritage Foundation, whose notice of their interest in purchasing art has recently been featured in Orientations magazine. The Foundation is purchasing rare and meaningful Korean cultural properties that are put up for auction or owned by art dealers and individuals. Their website is here.