Royal favourite: The Duchess of Cambridge in a Seraphine coat The Duchess of Cambridge's favourite maternity brand has listed on the London Stock Exchange with a £150million valuation. Shares in Seraphine, which floated under the ticker 'Bump', ended the day at 285.5p. Its private equity owners Mayfair Equity Partners, which backed a management buy- out in December, cashed out £10.9million of its stake, but retained a holding of 42.7 per cent, worth £62million. Chief executive David Williams sold £1.8million of shares, leaving him with a £6.8million stake, and brand director Chelsey Oliver pocketed £1.2million, retaining a £3.8million stake. The company and managers have earned a return on their investment of more than 70 per cent in just eight months.