The chief executive of BlackRock, the world’s largest asset manager, has voiced concerns that new EU rules set to come into force in January could lead to a dearth of research coverage focused on smaller listed companies.

The US asset manager, which yesterday reported $96bn in net inflows during the third quarter to help assets under management edge closer to $6tn, will absorb research costs under the updated Markets in Financial Instruments Directive — a wide-ranging set of rules that will force the separation of brokerage and research costs.