Shares in IMI PLC (LSE:IMI) fell as the fluid engineer said it was dealing with a cyber security incident, where unauthorised access had been gained to the company's systems.
The FTSE 100-listed company said it brought in cyber security experts to investigate and contain the incident as soon as it realised.
The IMI website appeared to be working as usual at just after 8am.
"In parallel, the company is taking the necessary steps to comply with our regulatory obligations," it said, adding that it will provide an update "as and when appropriate".
Shares in IMI fell 1.7% to 1,929p in early trading.
Rising cyber threat
In December, the UK's National Cyber Security Centre flagged an increase in serious security threats at companies across the country last year.
The tech arm of GCHQ revealed that a total 430 cyber security cases required support from its incident management team.
This included 12 maximum severity incidents, up 16% year-over-year, and the number of nationally significant incidents also rose from 62 to 89,
A total of 347 reports involved some data exfiltration and extortion, with 317 of these involving ransomware, up from 297 the year before.