Financial services firms are still worried about implementing the European Union's Markets in Financial Instruments Directive (MiFID), with IT integration high on the list of concerns, new research has shown.

MiFID comes into force in November and its successful implementation and compliance is highly dependent on IT systems.

The directive's "best execution" clause – which requires financial services providers to "take all reasonable steps to obtain the best possible result, taking into account price, costs, speed, likelihood of execution and settlement, size, nature or any other consideration relevant" – is causing particular concern, the survey conducted by compliance intelligence firm Complinet found.

The survey of 86 compliance, risk management and legal professionals working in financial services found that 50 cited best execution as an area of high concern.

IT systems integration was mentioned as a key Mifid implementation worry by 32 respondents, with the same number concerned about record keeping.

Home and host state reporting regulations were mentioned by 33 respondents, with 38 worried about client categorisation.

Greg Kilminster, group managing director at Complinet, said: "Part of the problem with best execution is that the wording in the directive is not very specific. Our customers are telling us that the guidance provided by the EU and by the UK Financial Services Authority is not yet clear enough for them to be sure what their obligations are.

"With less than five months to go, they are still having to compare different interpretations and take a view on what best execution means in practice for their firm. This level of uncertainty is clearly causing concern."

Last week, the London Stock Exchange announced a range of services to support MiFID compliance by its members and other market participants.