The loan to Ravi Kailas was made without prior approval of the utility’s board, the company said.
Mytrah has not confirmed who the loan was from, but in a statement said it was for "the purchase of a property which is not related to the company’s operations".
Kailas has made arrangements for the full amount of the loan to be repaid by the end of next week, the company added.
Mytrah’s board will engage an independent law firm to review the transaction before updating shareholders, the utility said. The company's share price fell by nearly 13% on 10 October.
Mytrah Energy has 615.3MW of online projects in India, according to Windpower Intelligence, the research and data division of Windpower Monthly.