Currently in Platinum, having finished Rank 1 of my Plat division in S1, promoted to Diamond in S2, fell to Platinum in S3, returned to Diamond in S4, crashed back to Plat last second in S5, and coasted back up to Diamond in S6. I think I'm a good predictor but then again I would think that.

Take note: the market resolves NO if I'm demoted to Platinum at the end of S5, and YES if I'm somehow promoted to Masters.