Citigroup is considering raising its stake in Pudong Development Bank (PDB), the country's third-largest listed lender, to as much as 20%, Reuters reported. Citigroup, the world's largest financial services provider, paid US$72 million for 4.6% of the bank in January 2003 and is pondering additional investment in response to purchases made by rivals such as HSBC Holdings and Bank of America in larger Chinese banks. Based on PDB's current share price, Citigroup would have to pay as much US$617 million, although foreign investors often secure steep discounts.