Schroder Salomon Smith Barney (SSSB) has sold a £1.8bn (€2.9bn) block of shares in GlaxoSmithKline, the UK pharmaceuticals company, at the tightest discount achieved in the UK on a trade of this size in recent years.

The bank sold 100 million shares in GlaxoSmithKline at £17.80, a discount of 1.9% to the previous night's close. That is the tightest discount on a UK block trade over £500m in the past five years.