Guarantee Mortgage Corp. is one of the West Coast s leading independent mortgage brokerage companies. Began operations in San Francisco in 1991, with 11 offices in California and Oregon, it offers a range of mortgage financing products and services for borrowers and the real estate community. The firm offers single family, multi-family and commercial loans. Guarantee Mortgage Corp., a Better Business Bureau accredited business has received approval to lend in California, Hawaii, Oregon, Washington and Colorado.