Royal Bank of Scotland Group Plc sweetened its 71.1 billion-euro ($98.1 billion) offer for ABN Amro Holding NV by increasing the cash portion, seeking to trump Barclays Plc in the world's biggest banking takeover. Royal Bank, which is bidding with Banco Santander SA of Spain and Fortis of Belgium, offered 38.40 euros a share for the biggest Dutch lender and raised the cash portion to 93 percent from 79 percent, the banks said in a statement today. Barclays's all-stock offer of 34.49 euros a share is 11 percent lower. Bank-Merger Mania ! Who is next ?