Mortgage rates

But even if plowing back into Treasuries proves to be a winning trade, sticking with it won't be for the faint of heart. 

Buyer affordability has decreased by almost 22% in the past year, according to the Mortgage Bankers Association.

Persistent inflation concerns drove the 30-year average up 41 basis points this month.

U.S. government bonds slid across the curve, with the 10-year rate heading for the highest close since Nov. 9.

Investors are concerned that the Fed could raise rates 50 basis points at its next meeting and are pricing that risk into the 10-year Treasury.

But with rates turning back up this past week, activity could fall in February, Black Knight Optimal Blue said.

Both Zillow and Black Knight Optimal Blue recorded significant increases, but the Freddie Mac survey only reported a 3-basis-point rise.

More than half of borrowers paid 0.5 points or more to cut their interest rate for the life of the loan, while just 3% chose the short-term option, Black Knight said.

Since breaking above 7% in November, the 30-year fixed is now down nearly a full percentage point, Freddie Mac said.

The Federal Reserve slowed its drive to rein in inflation and said further interest-rate hikes are in store as officials debate when to end their most aggressive tightening of credit in four decades.