Not sure about the US but since i am based in switzerland, i can safely say the second hand value of rolexes in switzerland are definitely better than iwc.....but you are right that the WIS here is also into IwC and other brands like JLC, bucherer, etc......
Having said that, rolex is a mass produced luxury watches that sell very well in any market and have also been a market leader (based on annual sales figure) for many consecutive years worldwide, i would be surprised if it is not as popular as IWC (or even more popular) in the US market....but, again i could also be wrong....
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