The Exchange, owner of Exweb, and Legal & General have signed a new five-year contract for use of the Exweb portal.
A third successive term for prime minister Tony Blair and the Labour Party has helped to lift shares on the FTSE 100 by the end of the week.
UK indices are relatively unchanged after the Labour party secured an unprecedented third successive election victory.
Three-quarters of FTSE 100 constituents are making gains this morning as the market shrugs off politics to focus on improving bottom lines, while also shrugging off poor news from the retailing and IT sectors.
Heavy weightings helped the FTSE 100 gain 21.30 points to 4,882.50 by the close, as investors bought into the biggest banking, telecoms and pharmaceutical companies.
A big jump in profits reported by British American Tobacco has helped the FTSE climb about 16 points to 4,876 this morning.
In London the FTSE 100 Index closed up by 0.8 points a short while ago to 4790.2.
In the UK the FTSE 100 Index has closed 15.60 points higher to 4864.90 points a short while ago, led by British American Tobacco.
In the UK, the FTSE 100 index has fallen sharply this morning, losing 80 points to 4,811 points in a delayed reaction to its counterpart index in the US.
In the UK the FTSE has remained steady after an early morning fall, closing the day 53.80 points lower to 4,891.60 points at its close.