GEMs (Growing-Equity Mortgages) Love Machine 14 years ago GEMs (Growing-Equity Mortgages)Mortgages wherein yearly increases in monthly installments are adjusted towards outstanding principal and this serves to reduce the remaining loan term.Recommended for you:Graduated-Payment Mortgages (GPMs)Growing-Equity MortgageNegative AmortizationSavings-Savy Borrowers Look to Credit Unions for 5-Year-Fixed Mortgages