By Lars Mucklejohn Challenger bank Oaknorth has posted a jump in annual profit on the back of higher lending and an expansion into the US as it looks forward to a potential IPO. The business-focused bank reported a 23 per cent increase in pretax profit to £187.3m in 2023 from £152.3m in 2022. Oaknorth said its total loan book grew 22 per cent to £3.8bn. The London-based bank specialises in lending to businesses with revenues of between £1m and £100m and has loaned around £10.2bn since it launched in September 2015. Since it launched in the US in the second half of 2023, Oaknorth has lent aroun…