New Delhi, June 25 -- For years, Tata Sons Pvt. Ltd. has been fighting one battle above all others-staying private. And the RBI may have just made that fight a little easier.

The Reserve Bank of India's updated circular on non-bank financiers has dropped a definition that had caused considerable alarm at Bombay House. Back in April, RBI had defined "indirect public funds" in a way that seemed to rope in Tata Sons, since group companies like Tata Steel, Tata Chemicals, and Tata Power hold equity in it. That definition is now missing from the updated guidelines.

Why does this matter? Because if Tata Sons were classified as receiving indirect public funds, it would almost certainly have been pushed toward a mandatory listing, something the...