Mortgage rates are skyrocketing with one real estate firm reporting a 50-basis point hike for the 30-year, fixed-rate mortgage in just the past week.

That honor goes to Zillow, which released data showing that on Tuesday the 30-year, FRM hit 4.38%, up 50 basis points from seven days ago.

A week ago, the same mortgage rate came in at 3.88%, according to data from Zillow. 

And Zillow [stock Z][/stock] isn’t the only one reporting high rates. Last week’s Freddie Mac 30-year, FRM came in at 3.93%, while Bankrate data showed mortgage rates at 4.12%. 

While rates tend to differ from entity to entity, the speed at which they’re rising has remained consistent. 

Zillow’s director of Mortgage Marketplace, Erin Lantz, believes there will be some more fluctuation still to come, including dips back lower. However, the longer term direction is up over the next 12 to 18 months, she told HousingWire. 

“Last week rates spiked to levels not seen since July 2011 after Federal Reserve Chairman Ben Bernanke reiterated the Fed’s commitment to scale back its stimulus program later this year,” said Lantz. 

She added, “This coming week, we expect rates will be volatile as the market recalibrates and determines whether we’ve reached a new plateau near 4.5% or whether this week’s rate spike was an overreaction that warrants a downward adjustment.”

But what does this mean for the housing industry? It’s been awhile since the markets have had to deal with interest rate volatility, and it’s creating some major anxiety. 

Just yesterday Fannie Mae’s chief economist, Doug Duncan, told HousingWire that once rates rise 100 basis points, home sales may begin to slow. With a 50 basis-point jump in seven days, those 100 basis points don’t seem too far off. 

Refinancing activity is expected to screech to a hault as rates continue to increase. In fact, last week the Mortgage Bankers Association noted its refinance index fell 3% from the previous week.

Once mortgage rates rise above 4.5%, half the mortgage market may not be refinancable based on rate incentive, according to analysts for Goldman Sachs. 

Bond investors have started preparing for the return of interest rate volatility as well. Once rates begin to shift outside of exterior influence, convexity and other interest functions should once again begin to play a critical role in the bond market.

So only time will tell just how volatile these rates will get. In the meantime, all we can do is hold on tight and hope for the best.

“It is impossible to predict,” said Lantz. “However, we expect there to be a lot of volatility, probably between 4.5% to 5%.”