Fast-growing fresh online dogfood operator Butternut Box almost doubled sales last year thanks to international expansion, but losses reached almost £25m as it continued to plough cash into growth.

The dogfood subscription specialist reached sales of £69.5m after annual growth accelerated from 50% to 99%, revealed newly filed accounts for Dogmates Ltd for the year to 25 December 2022.

This sales jump was driven by the acquisition of new customers in the UK and abroad, positive customer retention and the expansion of its product offering.

Gross margins also rose from 35.5% to 37.9% as it reaped the benefits of investment in production efficiency, pricing and economies of scale.

However, the group’s operating loss increased by 68%, from £14.9m to £24.9m. That was driven by significant investment in R&D and marketing – which underpinned its expansion to new geographies – and increased headcount.

Butternut Box pointed out its operating loss as a proportion of turnover decreased during the period and said this trend would continue.

In the meantime, it has continued to invest in growth in 2023, with the acquisition of Polish fresh dogfood player PsiBufet in April to boost its European footprint.

Meanwhile, investors continue to back its efforts to scale up and solidify its position as Europe’s largest fresh dogfood player. The business raised a further £280m in September, led by new investor General Atlantic and long-time backer L Catterton.

This latest fundraising, in addition to the £100m of capital it had previously raised, was reported to value the company at over £500m.

A spokesperson said: “We’re thrilled about the continued momentum behind fresh dog food that our growth represents and are incredibly thankful to our customers for their support. In 2023 we’ve further expanded our fresh offering to new European markets whilst improving our range and service.

“Throughout this period we’ve continued to invest in our supply-chain by keeping our commitment to using human-quality ingredients despite rising inflation. Now with new funding, we’re building on this momentum in the Fresh category led by our mission to deliver health and happiness to dogs and their humans.”