This excerpt taken from the LRCX DEF 14A filed Oct 10, 2006.
The Wall Street Journal or a similar publication. If no sales are reported as having occurred on the Value Date, Fair Market Value shall be that closing sales price for the last preceding trading day on which sales of Shares are reported as having occurred. If no sales are reported as having occurred during the five trading days before the Value Date, Fair Market Value shall be the closing bid for Shares on the Value Date (or on the last preceding date on which a closing bid for the Shares was made). If Shares are listed on multiple exchanges or systems, Fair Market Value shall be based on sales or bid prices on the primary exchange or system on which Shares are traded or quoted.