NerdWallet said former Citigroup banker Simon Williams is joining the consumer finance startup advised by Vikram Pandit, swelling the ranks of senior financiers helping the company.

Williams, former chief executive officer at Citibank's retail banking unit and ex-group head of wealth management at HSBC Holdings Plc, has been elected to join the company's board of directors, according to a statement Wednesday.

San Francisco-based NerdWallet, which offers consumer advice on financial services such as credit cards, insurance and loans, brought in former Citigroup CEO Pandit as an adviser to its board in May alongside James D. Robinson III, the former CEO of American Express Co.

Tim Chen, a former hedge fund analyst who founded the company in 2009, has hired more than 270 staff from firms such as JPMorgan Chase & Co. and LinkedIn Corp.

The company said Camelot Financial Capital Management LLC, where Williams is CEO and chairman, invested $5 million in NerdWallet, bringing its Series A funding to about $69 million.