Shares in Oxford Nanopore Technologies PLC (LSE:ONT) fell 16% to 101.2 pence after the company said first-half trading had come in below management expectations.
The maker of nanopore-based technology for analysing DNA and RNA, expects revenue of around £116.5 million for the six months to 30 June.
That represents growth of about 10% on a reported basis, or 12% at constant currency.
The shortfall principally reflected sharp declines in two regions.
Revenue in China fell around 16%, hit by tighter export control restrictions and changes to the company's commercial operations there.
Sales in the Middle East dropped about 14%, reflecting the ongoing geopolitical situation.
Stripping out those two markets, group revenue grew around 16% at constant currency.
The timing of customer orders and contract wins in the Americas also weighed on performance.
The company kept its full-year guidance for constant currency revenue growth within the previously stated range of 21% to 25%.
However, that range depends on additional collaboration and licensing revenue expected in the second half, some of which is one-off in nature.
Excluding those opportunities, underlying growth is expected to be 16% to 20%.
Oxford Nanopore continues to expect a materially stronger second half, supported by momentum in applied markets and the ramp-up of secured business.
Full-year gross margin guidance remains around 62%.
The company also reaffirmed its target of reaching adjusted earnings breakeven during the 2027 financial year.
Cash and liquid investments stood at around £234.5 million at the end of June, down from £302.8 million at the end of 2025.
Applied markets revenue grew about 22%, led by clinical sales up 35% and biopharma up 25%.
Research revenue rose around 5%, held back by the roll-off of several large projects.
Chief executive Francis Van Parys said operational progress continued, with further gains in gross margin and disciplined cost control.
Interim results are due on 19 August.
