The ₹3,650-crore rights issue of Piramal Enterprises will open for subscription on Tuesday and close on January 21. The offer is priced at ₹1,300 a share. The entitlement ratio has been fixed at 11 shares for 83 held in the company. Shareholders whose names had appeared on its book on December 31 are eligible to participate in the buyback, which is through the tender offer route. Investors will monitor the response to the issue, even as promoters said they are committed to its success.