Royal Mail share jump is 'froth', says Vince Cable
11 October 2013 Last updated at 10:36 BST
Royal Mail shares rose more than 38% to 456p at the start of conditional dealings on the London Stock Exchange.
The hugely oversubscribed sale was priced at 330p per share at the top of its expected range and valuing the near 500-year-old company at £3.3bn.
Business Secretary Vince Cable dismissed the market price debut is "froth and speculation".