Shares at wireless technology firm CSR have sunk after it said sales would be hit by lower-than-expected demand from a major customer.
Up to 40% of mobiles will feature Bluetooth by the end of 2006
CSR shares slumped 25%, wiping £350m from its stock market value.
Customers including Nokia, Microsoft, Dell and Sony use CSR's Bluetooth technology to link their computers and mobile devices without cables.
The popularity of Bluetooth mobiles had helped CSR double profits to £14m in the first three months of 2006.
But updating the markets on its outlook for the second half of the year the Cambridge-based company said customer demand in the second half of 2006 would not be as strong as anticipated, "principally due to changing purchasing patterns at a headset customer".
As a result it lowered its third-quarter sales estimate by 10%.