By Carolyn Cohn and Rhea Binoy LONDON (Reuters) -Amazon.com Inc is launching a home insurance portal in Britain and has signed up three big-name insurers as it pushes further into financial services across the globe. Ageas UK, Co-op, and LV= General Insurance, a unit of German insurer Allianz, will provide third-party services initially, Amazon said on Wednesday, and it hopes to add more insurers “early next year”. Moneysupermarket.com’s shares slumped more than 8% on Wednesday following the news that Amazon will be stepping into the insurance-price comparison market. “Amazon will be a major t…