Related person definition determines when corporate veil may be lifted to align valuation with economic substance. For section 245K, related person is identified by specified ownership or entitlement thresholds (more than fifty per cent. shares, voting rights or profits, or HUF karta status), applying retrospective look back where indicated. Under the pre 2000 Central Excise Act, the definition contains a core association test (direct or indirect business interest) plus an inclusive list (holding company, subsidiary, relative, distributor, sub distributor) to allow lifting the corporate veil and reach economic realities for valuation.