SHARES in Wolfson Microelectronics slumped 16% after it warned final quarter sales are likely to be lower than expected and a major customer, believed to be Blackberry, has cancelled a product roll-out.

The Edinburgh semiconductor maker said revenue for the third quarter, ended September 29, is likely to come in around $44 million (£27m) with its largest customer, Samsung, accounting for 35%.

However the cancellation of "product programmes" at a major client, which analysts suggested is Blackberry, plus delayed product launches at other customers will see fourth quarter revenues come in between $40m and $50m.

While Wolfson, a spin-out from Edinburgh University, does not comment on individual customers it has provided parts for consumer electronics giants such as Lenovo and Sharp as well as Amazon's Kindle devices.

Blackberry recently completed a major strategic review, which saw it confirm plans to shed 4500 staff and move away from producing consumer devices. It has since reported a quarterly net loss of £600m and agreed a £3 billion deal to be acquired by Fairfax International, its largest shareholder.

In the trading update Wolfson said projects with several customers were expected to ramp up in 2014, mitigating the lost revenue from the cancellation.

It also indicated that the other customer product delays it highlighted were likely to roll over into the first half of the next financial year.

Indeed it highlighted "strong widespread traction" at all other major customers saying design-ins, where Wolfson products were selected for devices, were progressing well.

Mr Hickey had said at Wolfson's half-year results announcement in July that revenue would slow in the third quarter but he was hopeful of returning to profit in the final three months of 2013.

It has previously been suggested the business needs to make quarterly revenue of around $50m to be in a break even position.

Amit Harchandani at Citi said the contribution from the largest customer, 35% against 60% in the first half of the year, was a positive sign for Wolfson.

He said: "Although we did expect the contribution of the largest customer to decline in Q3, the extent of decline suggests accelerating traction for Wolfson's products outside Samsung, and is therefore encouraging in our view."

Mr Harchandani expects full year revenue at Wolfson in 2014 to be around $222m

Lorne Daniel, at Finncap, said he would have liked to have seen more detail on gross margins and suggested full-year revenue for 2013 at Wolfson was now likely to be in line with the near $180m posted for the 12 months to December 30, 2012.

Numis kept its add rating on Wolfson's shares, suggesting it saw little change to prospects in 2014 with an expectation of market share gains and stronger selling prices.

Shares in Wolfson closed down 27.5p to 147p.