To remove most of the objectionable features of mortgage investment, companies have been formed, and have most successfully proceeded to take mortgages and assign them to investors, guaranteeing the payment of principal and interest, and assuming all responsibility for their collection, and for the various other necessary functions the mortgagee finds so burdensome. A charge of 1/2% per annum is made for the guarantee company's services, and this comparatively small fee has made this form of mortgage investment so popular that in the past three years the sale of guaranteed mortgages has increased to double what it was the previous three years.