(Paul J. Richards/AFP/Getty Images)

The rate on a 30-year fixed mortgage, the most popular home loan product, made its biggest jump in three months after a volatile week in the bond market.

The movement of the 10-year U.S. Treasury typically is a leading indicator of where mortgage rates are headed. When yields rise, home loan rates tend to follow.

The yield on the 10-year Treasury spiked to 1.73 percent Tuesday, its highest close since late June. It went up 19 basis points (a basis point is 0.01 percentage point) for its biggest four-day gain in 14 months.

After ending last year at 2.27 percent, the yield on the 10-year note had plunged to a record-low 1.36 percent on July 8. Since then, it had been hovering mostly between 1.5 percent and 1.6 percent.

Uncertainty over when the Federal Reserve will raise the Federal Funds Rate has driven down long-term bond prices, causing yields to move higher. Investors will be looking to see what happens at next week’s Federal Open Market Committee meeting.

A summer of low, stable mortgage rates may be coming to an end. Higher rates will make home buying more expensive, which would cause a drag on the housing market.

Bankrate.com, which puts out a weekly mortgage rates trend index, found that more than half of the experts it surveyed believe rates will go up in the coming week.

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According to the latest data released Thursday by Freddie Mac, the 30-year fixed-rate average climbed to 3.5 percent with an average 0.5 point. (Points are fees paid to a lender equal to 1 percent of the loan amount.) It was 3.44 percent a week ago and 3.91 percent a year ago. The 30-year average hadn’t been at or above 3.5 percent since June 23.

The 15-year fixed-rate average had a more modest gain, rising to 2.77 percent with an average 0.5 point. It was 2.76 percent a week ago and 3.11 percent a year ago.

The five-year adjustable rate average ticked up to 2.82 percent with an average 0.4 point. It was 2.81 percent a week ago and 2.92 percent a year ago.

“The 10-year Treasury yield rose … to 1.73 percent, its highest level since Brexit,” Sean Becketti, Freddie Mac chief economist, said in a statement. “The 30-year fixed-rate mortgage followed suit, rising 6 basis points to 3.50 percent this week. This is the first week since June that mortgage rates were above 3.48 percent, snapping an 11-week trend.”

Meanwhile, mortgage applications moved higher this week, according to the latest data from the Mortgage Bankers Association.

The market composite index — a measure of total loan application volume — increased 4.2 percent from the previous week. The refinance index increased 2 percent, while the purchase index increased 9 percent.

The refinance share of mortgage activity accounted for 62.9 percent of all applications.

“Real median income rose for the first time since 2007 last year, increasing by 5.2 percent according to newly released data from the U.S. Census Bureau,” said Lynn Fisher, MBA’s vice president of research and economics. “Continued strength in employment has been supporting a home purchase market that has seen consistent year-over-year growth in 2016. Last week, refinance activity was buoyed by average mortgage interest rates moving down slightly despite a late rally in the 10-year U.S. Treasury yield.”