The prospect of weakening international demand to buy U.S. debt, at the same time as Uncle Sam may need to begin selling more debt to make ends meet, likely helped push mortgage interest rates to their highest point in months early this week.

Average prime 30-year, fixed mortgage rates quoted on Zillow increased sharply early this week, touching 3.88 on Wednesday, up from 3.74 a week ago.

Mortgage rates were flat over the two previous weeks – including after Friday’s December Jobs Report, which showed reasonably strong but slower-than-expected employment growth. But jumped on Monday and Tuesday, driven by a stronger economic outlook in Europe and Japan and the prospect of larger fiscal deficits in the U.S. after Congress decided to defer considering entitlement and welfare cuts. Together, these imply softer international demand and stronger domestic supply for U.S. long-term debt, which should push up interest rates.

Mortgage rates may stabilize this week, pending new data. Absent major economic or geopolitical developments, these kinds of sudden moves in rates are typically followed by a reevaluation and, often, a temporary pullback. That calculus could shift on Friday if scheduled reports show inflation and retail spending in December were stronger than expected.

In addition, markets could respond to anticipated comments by New York Fed President William Dudley on Thursday afternoon. Dudley is set to retire from the New York Fed in mid-2018, but he remains one of the FOMC’s thought leaders and is likely to continue playing an important role in shaping monetary policy over the next few months.