A billionaire ally of President George Bush could face a criminal investigation into insider share dealing after selling £100million of shares just days before Societe Generale's rogue-trader losses were reported. Robert Day, a member of the French bank's board, disposed of a million shares on January 9 and 10, plus a further 500,000 on January 18, according to official disclosures to Autorite des Marches Financiers (AMF), France's market regulator. The £3.7billion losses at the bank were not disclosed to the public or investors until January 24, despite reports that Societe Generale bosses were aware of the crisis several days earlier....