Independent investment banking and broking group Numis said its core business performance strengthened in the second half of the year to 30 September, after a tough start to the year.Combined commission and trading revenues reached record levels for the six months to 30 September as market activity picked up and Numis gained market share.Cash and cash collateral balances amounted to £70.0m at the end of September, up from £64.9m at the end of March. The group has no external debt.'Our focus on maintaining a strong balance sheet has allowed us to continue to build our franchise even during difficult market conditions,' said chief executive Oliver Hemsley. 'We have won new corporate clients and have attracted high calibre employees whilst placing great emphasis on cost control,' Hemsley continued, adding that the board remained optimistic about the future of the business.