Trade Me's shares dropped as much as 9% after the company reported a small rise in first-half net profit.
A jump in expenses and flat sales in its biggest business were factors.
The online auction website reported a rise of nearly 2% in net profit to $38 million for the six months to December, compared with $37.3 million last year.
Sales grew 7% to nearly $86 million, with the site's classifieds business experiencing 17% higher sales.
However, sales in the main second-hand auction business were flat and the company says it's making efforts to restore growth in that part of its operations.
Expenses rose 19% to more than $25 million, largely due to the company hiring about 50 more people as well as extra marketing costs.
Trade Me will pay a first-half dividend of 7.6c a share, fractionally higher than last year.