A publication by Moore in 2001 states that only 5 percent of patent lawsuits reach a verdict, “which the 1996 AIPLA estimate of median litigation costs [out-of-pocket only] cites at $1.2 million.” Another 49 percent of cases were dropped before the start of discovery (!), which cases presumably cost relatively little. The remaining cases – 46 percent – each incurred some costs, with the median cost per case through discovery being $600,000. It is not clear from what I read whether these figures combine the spending of both (or all) sides to the litigation.
The page [www.nap.edu/openbook/0309086361/html/69.html] which included these findings, plugged in $10,000 for the cases dropped before discovery and then calculated an expected cost of litigation per patent case of $349,900.
An article in the Chicago Daily Law Bulletin (Aug. 26, 2003 ) by Richard P. Beem updated the AIPLA costs to its 2001 Economic Survey: $797,000 through discovery and $1,499,000 through trial. That is a 25 percent increase over five years in the cost of tried cases.