definiens: shallmean, as of any date of detennination, the average of the closing sale prices of ChironStock during the 10 trading day period immediately preceding such 9ate ofdetermination on the principal United States securities exchange registered under theExchange Act on which [COMPANY] Stock is listed, or, if Chicon Stock is not listed on anysuch exchange, the average of the closing sale prices or the closing bid quotations ofthe [COMPANY] Stock during the 10 trading day period preceding such date of determinationon the NASDAQ National Market or any comparable system then in use, or, if no suchquotations are available, the fair market value of the [COMPANY] Stock as of such date ' ofdetermination as detennined in good faith by a majority of the Independent Directors, f:\'ubsc4 .doc9nm5995SF02755 . . G)r?-