The Share Centre has given Prudential a 'buy' rating, saying that the insurer is "attractive for investors" after another set of strong results on Tuesday.The company's US and Asia businesses helped the group to boost first-half operating profits by 17% to £1.52bn despite a drop in UK annuity sales sparked by government pension changes. "Prudential delivered another set of strong results this morning beating consensus estimates, with operating profits up in all major geographies and divisions," said Sheridan Admans, investment research manager at The Share Centre."We continue to recommend Prudential as a 'buy' for investors looking for a positive investment idea that spans the US, Asia and the UK. The Asian growth story continues to remain highly attractive along with strong UK and US operations."The results were warmly received by the market on Tuesday with the stock up 1.8% at 1,363p by 11:16.BC