The financial ombudsman (FOS) dealt with almost 400 complaints relating to collapsed stockbroker Wills & Co in the first half of the year, finding 99% in favour of the consumer.
According to data published today by the FOS, there were 387 investment complaints referred to it about Wills & Co in the first six months of this year.
The stockbroker was declared in default in July by the FSCS after the FSA banned the company from giving investment advice in January.
It was fined £49,000 by the FSA in 2007 after being found guilty of mis-selling penny shares.
In the first half of 2010, banks and insurers continued to dominate the complaints figures.
Five financial services groups continued to have more than 3,000 complaints each, which together accounted for 47,507 cases - over half of all the new complaints received by the ombudsman during this six-month period.
The FOS handled 12,750 new complaints relating to Lloyds TSB Bank in the period, while almost 8,000 complaints related to Barclays Bank.
Elsewhere, the Aviva group, comprising Aviva Health, Insurance, Insurance UK and Life and Pensions UK, was subject to 1,254 complaints.
During the six-month period, the ombudsman service received a total of 84,212 new complaints - a small increase on the 82,136 cases received in the second half of 2009.
Of these new cases, 89% related to 160 financial businesses out of more than 100,000 businesses covered by the ombudsman.
The FOS upheld an average of 44% of complaints in favour of consumers, compared to 53% in the second half of 2009.
Chief ombudsman Natalie Ceeney says: "The latest set of complaints data shows that some businesses are really committed to ensuring that complaints are handled well, and are used to inform and improve the service they offer their customers.
"However, the complaints data also shows there is still more that some businesses need to do to ensure that complaints are properly investigated and fairly resolved."
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