Reason to believe: reopening assessments require concrete prima facie material before issuing notices, not mere suspicion.

Reopening assessments requires an honest and reasonablereason to believe that income has escaped assessment supported by material or prima facie facts; ITOs must state the factual basis in reports and Commissioners must independently satisfy themselves of prima facie grounds rather than mechanically granting sanction, since notices issued on mere suspicion or vague beliefs have been held invalid.

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