The price of the Nikon 200-400mm f/4G ED VR II lens just dropped by $1,000 to $5,647.90 at Amazon and B&H (still listed for $6,649 at Adorama). The grey market version is currently priced at $6,299. I am not sure what is going on since Nikkor tele-photo lenses are rarely discounted and this lens is not part of the ongoing rebates. One possible scenario is that Nikon may soon update this lens with a fluorite element (FL).
FIY: the price of the 200-400mm f/4G lens when announced was $6,999.95.