As I said, it's a mathematical formula that factors square roots of conquest gains/losses and points per player and abp/dbp, etc. blah blah math math. As soon as they start taking losses, they will drop as a loss will factor against them more due to their smaller alliance number and lower points (city and abp/dpb) - but right now, at this moment they haven't so their number is strong. Plus, maybe the way they have built their ocean is preventing anyone from taking any cities. This would also be indicated in the formula...that if they've built an impenetrable ocean, then they deserve a high ranking. but once their ocean is breached with a city takeover, their ranking will fall.