Complex sentence: He finally persuaded the "City Bank of New York", today Citibank, to run a 6-month trial, which was however not continued--surprisingly not due to technical insufficiencies, but to lack of demand.
Split into simpler sentences: He finally persuaded the "City Bank of New York", today Citibank, to run a 6-month trial. The trial was however not continued--surprisingly not due to technical insufficiencies, but to lack of demand.