Nationwide, the median loss per loss-making sale is around $20,000. Investors were worse off than owner occupiers, losing $44,500 per sale.
Another trend revealed in the report was that the median hold period for loss-making properties had decreased from eight years in the previous quarter to just under seven.
The hold period in Auckland dropped to just one year in the June quarter, down from 2.3 years in the previous quarter.
"This means half of all Auckland properties selling at a loss were owned for less than a year," CoreLogic head of research Nick Goodall said.
Goodall said the report showed the result of the general market slowdown and uncertainty about the future.
"We know from consumer confidence surveys that house price expectations have weakened. This new data shows a higher number of people who bought in the past year are more cautious and choosing to sell earlier," he said.