New Delhi, Sept. 21 -- There was a time when the Tata Group did not need elaborate rules to explain where ownership ended and management began.

For more than half a century, J.R.D. Tata chaired Tata Sons while the Tata Trusts owned the holding company. The Trusts owned the institution; Tata Sons presided over the businesses; and JRD stood between the two. The arrangement worked in large part because JRD was larger than any of the offices he occupied. His personal authority, built over decades and extending well beyond the boardroom, gave the House a centre of gravity that no set of Articles could have provided.

JRD could surround himself with formidable executives and give them considerable autonomy because he did not regard stewardship...