What’s driving this week’s spike in mortgage applications?

What the heck? The Mortgage Bankers Association’s weekly mortgage survey indicates a 43% refinance increase and an overall 30.2% application spike for the week ending Jan. 10.
Mortgage rates are good-and-low, but they’ve been good, low and steady for the past several months.
Freddie Mac’s 30-year fixed rates averaged 3.93% throughout 2019. And rates have been at 3.75% or lower for the past 2 ½ months.
Why such an abrupt spike in refinance applications now?
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