Quest Software, which makes tools to help companies manage computer systems, has accepted a sweetened $2.17bn (€1.73bn) $25.75-a-share bid from Insight Venture Partners and agreed to the addition of Vector Capital to the buyout group.

Apple profits almost doubled in the last quarter, reflecting robust demand for the iPhone in China, as well as purchases of a new version of the iPad tablet, allaying the concerns that fuelled a 12% two-week slump in the stock.