Mortgage rates are going in two directions at once, with lenders cutting fixed rates to attract new business while they protect their margins by pushing up variable rates.The latest to move is AMP Bank, which will increase variable rates for owner-occupiers paying principal and interest, and interest only, by 15 basis points - effective March 8. Investment loan rates will also rise by 15 bps.The standard variable rate for an owner-occupier paying P&I with AMP Bank will rise to 5.43 per cent, and the basic variable rate will rise to 5.08 per cent.It's in part a reaction to S&P's downgrade on Friday for AMP Bank's long-term issuer credit rating from A to A-.S&P cut the short term rating to A-2 from A-1.AMP is in line with some other lenders on the direction of interest rates, but an outlier on the size of the hike.According to comparison site Mozo, Bank of Us, Defence Bank, ING and Liberty raised variable rates in February. Two of the lenders that cut fixed rates last month, Aussie and Macquarie, raised their variable rates.NAB, Bank of Queensland and its subsidiary Virgin Money raised variable rates in January.Meanwhile, fixed rates are falling. Comparison site RateCity says 22 lenders have cut rates on more than 150 fixed home loans so far this year.Mozo reports that AMP Bank, Aussie Home Loans, Citibank, Macquarie Bank, Westpac and its subsidiaries St George Bank, Bank SA and Bank of Melbourne all cut fixed rates in February.BankVic, CUA, Greater Bank and P&N Bank all cut fixed rates in January.Aussie cut its five-year rate by 40 bps and Macquarie cut its five-year rate by 30 bps.RateCity says the lowest fixed rates in the market include Suncorp's offer of 3.49 per cent for a one-year term, BankVic's offer of 3.58 per cent for two years, Bank of China's offer of 3.64 per cent for three years and Greater Bank's offer of 3.64 per cent for four and five years.The lowest variable rate in the market is 3.44 per cent from Reduce Home Loans and FreedomLend. New entrant Athena is offering 3.49 per cent for owner occupiers and 3.89 per cent for investors.Savings.com.au reported that loans.com.au yesterday announced the release of a new home loan product, with "an ultra-low interest rate" of 3.48 per cent (3.50 per cent comparison rate).That's Firstmac behind loans.com.au and Savings.com.au