Shares in emergency maintenance company HomeServe have fallen by around 7% amid rumours that the company is going to issue a profit warning.
High volumes of the shares were traded as London-based bankers speculated that it is preparing to tell investors it will not meet its financial targets.
In response a company spokesperson said "there is no new news".
HomeServe, which sells insurance for, and fixes homeowners' boilers and burst pipes, has been dogged by problems since October when it was accused of mis-selling policies to customers.
The company temporarily suspended telephone sales and launched a costly review into its marketing and training processes.
In April, HomeServe was fined £750,000 by Ofcom for breaching rules regarding phone call numbers.
And the following month, the regulator the Financial Services Authority put it under an investigation that is ongoing.
Customer numbers have fallen by 300,000 since the mis-selling accusations became public, hitting revenues and forcing HomeServe to shrink its business in the UK.