definiens: means, in the case of any Milestone Payment with respect to the achievement of the applicable Milestone, the average of the closing sale prices per share of Parent Common Stock as reported on the Nasdaq ( or other national exchange upon which the Parent Common Stock is then listed ) for the five ( 5 ) trading day perio d ending three ( 3 ) calendar days prior to the date such Milestone is achieved ( as adjusted, if applicable and appropriate, to reflect any reclassification, stock split, reverse stock split, dividend, distribution or other like change with respect to Parent Common Stock effected ( or for which a record date is established ) on or after the first day of such five ( 5 ) trading day period and on or prior to the date such Milestone is achieved ) . In the event that ( i ) the Parent Common Stock is no longer listed on N asdaq or another national exchange ( whether as a result of a merger of Parent into another Person, the acquisition of Parent or otherwise ) and ( ii ) the common stock of Parent ’s acquirer or successor -in - interest is listed on Nasdaq or another national excha nge, then such common stock shall be deemed to be Parent Common Stock for the purposes of this Agreement, including calculating the Parent Stock Value . In the event that at the time of the Milestone Payment, if any, the Parent Common Stock or the common st ock of the Parent ’s successor in interest, if any, is no longer listed on the Nasdaq or any other national exchange, the Parent Stock Value shall be the fair market value thereof as reasonably determined in good faith by the board of the Parent or its succ essor in interest, as the case may be