"There's still room for more of those flippers to leverage their money," he said.

The increase in flipped home sales can be an opportunity for credit unions to increase their loan portfolios, particularly in light of safeguards that are now in place, according to CU Appraisal Services President John Theobald.

"With the reemergence of home flipping, I see a good opportunity for credit unions to safely expand their home loan product offerings with things like renovation loans," Theobald said. CU Appraisal Services is a Dayton, Ohio-based company that solely serves the credit union market.

In the report, a home flip was defined as a property that "is sold in an arms-length sale for the second time within a 12-month period based on publicly recorded sales deed data collected by RealtyTrac in more than 950 counties," the company said. RealtyTrac analyzed sales deed data and automated valuation data for the report.

The number of home flippers in 2015 totaled 110,008 – the highest since 2007, when 130,603 investors flipped homes. The home flipper peak took place in 2005, when 259,192 investors flipped houses.

Blomquist said the increase in the number of home flippers demonstrates confidence in the housing market.

"This flipping trend is not just the domain of large investors," he said. "It's spreading to smaller investors."

Homes flipped last year yielded an average gross profit of $55,000, the highest since 2005, when the average gross profit reached $58,750.

Running counter to the national trend, the number of homes flipped in 2015 exceeded the 2005 peak in 12 metro areas. Pittsburgh saw the largest increase – 19% above the 2005 level – followed by Memphis with 18% more than the 2005 number and Buffalo with 12%.

Home flips increased in Lakeland, Fla. by 50% – the highest increase in the nation – followed by New Haven with a 45% increase and Jacksonville with a 41% increase. States with the highest share of flips were Nevada, with 8.8%, Florida with 8% and Alabama with 7.4%.

Theobald said that the Dodd-Frank Act provides safeguards to prevent house flipping market abuse that took place in the past.

"It was collusion between lenders and appraisers that led to the inflated values and bad house flipping practices of the past," he said. "Dodd-Frank has required credit unions and lenders alike to adopt internal policies and practices that prevent collusion and promote healthy appraisal management practices."

Theobald said credit unions should require two appraisals in a flipping situation and should accept the lower of the two in order to mitigate risk and inflated home values. He also said any "for sale by owner" and non-arms-length transactions should be examined carefully, adding that credit unions should use tools at their disposal to identify any potential overvaluation risk.