Concerns are mounting over the future of Coventry-based Cisco Gold partner Voyager Networks.
The unified communications specialist, established in 1993, is already on many distributors' watch lists after posting a string of results that show declining trade and operating losses.
But sources claim Voyager has seen its credit limits restricted by the insurers and that the firm is unusually late paying distributors.
Some end-user customers have also questioned the financial stability of Voyager, according to channel sources, and at least one implementing a VoiP system decided to place the business with another Cisco reseller.
The business is due to file calendar 2011 numbers imminently but its profit and loss accounts in recent years reveal the firm's deteriorating fortunes.
In 2006, sales fell to £8.5m from £9.2m in the previous year but operating profits rose from £93,000 to £323,000.
Ever since, Voyager's turnover has dropped year-on-year, down to £4.49m in 2010 - the last filed accounts - and in that timeframe it has consistently posted operating losses, which hit £502,000 in 2010.
Working capital has eroded from a positive position of £24,000 in 2006 to a deficiency of £1.24m in calendar 2010, so there is less money to fund the business.
"This is not sustainable," said one distribution insider.
Voyager Networks has refused to comment. ®