There's technically no minimum for members.
It's recommended that you get some, though. If you make a clan, make it official, and then nobody joins, you're out 20k TCs.
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20k, yeah. But not sure about 10 members because I did it with about 3/4. =D
You made a clan with three quarters of a member? What'd you do with the other quarter, assuming it wasn't you? I don't know many people likely to draw themselves out into quarters for anything...