5,441 crore, by Relay BV, a wholly-owned subsidiary of Diageo.
The open offer was earlier scheduled to start on January 7, but it was postponed in absence of necessary approvals.
An acquirer can go ahead with the open offer only after Sebi issues its "observations" on the same.
USL, the country's largest spirits company, is part of Vijay Mallya-led UB Group, whose aviation venture Kingfisher Airlines has been going through turbulent times for many months now and its licence is currently suspended.
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