Forbes published an article investigating the market for SCADA zero-day exploits in industrial control systems. The price of a SCADA exploit is theoretically unlimited, the price depends on a number of factors, including the offensive capability of the cyber weapon that triggers the flaw. Nation-state hackers are the most important actors in the market, but Gleg sells its pack mainly to private companies, for testing purposes. The number of companies that work in the SCADA exploitation is growing, a circumstance that leads to believe that this kind of service is increasing.”]
Source: http://securityaffairs.co/wordpress/41385/cyber-crime/scada-zero-day-exploit-cost.html