Mortgage News Daily says the index is driven by real-time changes in the actual lending rate table.
Separately, Freddie MAC said Thursday that 30-year fixed-rate mortgages averaged 6.65 percent as of March 2, up 15 basis points from the previous week.
The last time the 30-year was at this level, in mid-November 2022, a basis point is one hundredth of a percentage point.
Last week, the 30-year yield was 6.5 per cent. The average yield on 30-year bonds was 3.76% last year, Freddie MAC said.
The average rate on a 15-year mortgage rose to 5.89 percent from 5.76 percent the previous week. A year ago, the 15-year yield was 3.01 per cent.
Freddie MAC's weekly report on mortgage rates is based on thousands of applications received from lenders across the country that are submitted to Freddie MAC when borrowers apply for a mortgage.
As of Thursday morning, the average rate on a 30-year fixed-rate mortgage was 6.94 percent, according to separate data from Mortgage News Daily.
Demand for mortgages fell in the latest week as rates rose, according to a separate report from the Mortgage Bankers Association. Purchasing applications fell to their lowest level in 28 years.
"Given continued economic growth and persistent inflation, mortgage rates have bounced back and are edging up toward 7 percent," Freddie MAC chief economist Sam Carter said in a statement.
He added: "Now that interest rates are rising and affordability is being hampered, it is difficult for potential buyers to make a move, especially repeat buyers with existing mortgage rates of less than half the current rate."