Sam Mostyn has been appointed chair of the board of Citigroup Pty Ltd - Citi's retail banking business in Australia. Mostyn has been on the board since 2011 and currently chairs the remuneration committee. She replaces Dick Warburton, who is retiring. Mostyn is on the boards of Virgin Australia, Transurban Group and CoverMore Group. She is deputy chair of the Diversity Council of Australia. Ian Hammond and Ian Watt are also joining the Citigroup Pty Ltd board as non-executive directors. Westpac has hired Toby Dewar as its new head of media. Dewar is Telstra's general manager for marketing, sponsorship, media and change management. Before that he was media and sponsorship manager for McDonald's and client service director for agency Ikon Communications. Prepaid card supplier Emerchants has signed a contract with a European mobile phone recycling company, Redeem. Redeem offers reward cards as trade-ins for phones. The deal was done by Emerchants' UK subsidiary Store Financial Services.