Bank profitability after Vickers reforms proves a deeper worry on the markets than the death of North Korean leader Kim Jong-ilThree of the big four UK retail banking stocks were in retreat after George Osborne confirmed he would back almost all the recommendations of Sir John Vickers' Independent Banking Commission.Concern about the impact on profitability of proposed regulations to separate retail and investment banking functions left Lloyds Banking Group the biggest faller in the FTSE 100, down 1.035p at 23.465p. Barclays was down 5.5p at 165.95p, and Royal Bank of Scotland fell 0.6p to 19.4p. HSBC, which appeared to have battled hard for significant concessions, eased back 2.45p to 478.25p.Across the FTSE 100 gains were concentrated amo...