Shares in Homeserve, the emergency repair and service company (935p), have more than doubled in two years but still have further to go. The company has grown by giving customers instant access to plumbers and tradespeople but there is only a 30% penetration rate in boiler repair cover, which is the most mature area of this market. It is increasingly becoming the tied insurance repairer for large insurance groups and with water damage the most common cause of insurance claims, this is a huge under-exploited market. Keep buying.