Shares in Domino's Pizza dropped by more than 11% in early trading after the company posted a loss in profits in its interim results.
The company posted a drop of almost 10% in statutory profits for the first half of 2018, falling from £46.2m for the same period last year to £41.7m.
The fall comes despite a rise in UK and Irish sales by 8% and a rise in group sales to £616.6m. Net debt also rose - from £61m last year to £182.1m.
The stock market responded to the news in early morning London trading, with shares dropping by more than 32p to their lowest levels in almost a year.
The company put much of the blame on international expansion, with CEO David Wild stating Underlying Profit Before Tax will be "in line with current market expectations" by the end of the financial year.
He added: "It's been another good trading period for Domino's. In the UK, despite continued consumer uncertainty, we've achieved further like-for-like growth by maintaining our clear focus on product, service and value for customers.
"Our ongoing investments in supply chain infrastructure and our IT platform will support future growth and customer engagement."
He added: "Whilst our international businesses continue to make good progress with customers and sales, it has taken us some time to refine the operating model and cost base at store level, particularly in Norway.
"We are confident that the changes we have made will result in a better performance in H2, and believe that these businesses offer significant long term growth potential as we export our expertise in digital, supply chain and franchisee management."