Online-only retailer Kogan.com had its best holiday trading period ever in 2018, with both Black Friday and Boxing Day sales producing record days in the history of the business.

But subdued demand for new Apple products cut its revenue from global brands nearly in half for the six months to December 2018. Revenue from global brands was down 46.7 per cent compared to the previous corresponding period.

The company attributed this largely to the new GST law that went into effect last July, noting that several foreign websites selling into Australia are not complying with the law and therefore undercutting Kogan on price.

But slower iPhone sales also had a significant impact on the revenue decrease, since excluding Apple, Kogan’s revenue global brands actually grew 8.5 per cent.

The company posted a 23.6 per cent rise in revenue from exclusive brands and a 92.8 per cent rise in revenue from partner brands.

Gross margin for the first half of 2019 was broadly in line with the first half of 2018.

Kogan.com founder and CEO Ruslan Kogan said 2018 was the best Christmas the business has ever had and that the company’s customer-centric approach enabled it to deliver more items faster.

“The investments we have made in a nationwide logistics footprint enabled us to delight customers all over Australia with rapid delivery, along with the great value they have come to expect from Kogan.com,” he said.