definiens: as used in this sentence means Business Days on which suchexchange is open for trading . If at any time the Common Shares are not listed on any United States securitiesexchange or any other principal stock exchange and are not quoted on the OTC Bulletin Board, the Pink OTC Marketsor similar quotation system or association, the of the Common Shares shall be the fair marketvalue per share as determined jointly by the Board and the Holder ; provided, that if the Board and the Holder areunable to agree on the fair market value per share of the Common Shares within a reasonable period of time ( not toexceed ten ( 10 ) Business Days ) from the Company ’s receipt of the Exercise Notice ), such fair market value shall bedetermined by a nationally recognized investment banking, accounting or valuation firm jointly selected by the Boardand the Holder . The determination of such firm shall be final and conclusive, and the fees and expenses of suchvaluation firm shall be borne equally by the Company and the Holder