The firm, one of the world's largest providers of commercial finance, is understood to have chosen H&K as its primary corporate PR agency across Europe.
The move marks the first time GE Capital has brought in a single agency on a multi-jurisdictional brief, having previously used a number of different agencies in local markets.
Some of these local relationships are thought to be unaffected, but H&K will take on the UK responsibilities previously handled by Lansons Communications. GE Capital and H&K both declined to comment on the appointment.
GE Capital currently operates in 16 key markets across Europe and will call on H&K in each of the jurisdictions when the need arises, in addition to the agency's pan-European hub role in London.
In 2009, the firm went through a restructuring process that saw it combine a number of previously separate businesses under the GE Capital brand.
It is understood that the appointment of H&K is designed to help unify the brand's corporate message and present it as the leading provider of commercial finance to SMEs across Europe.
GE Capital has more than 500,000 customers in the EMEA region, offering financing in fields including corporate aircraft, vehicle fleets, equipment and healthcare.
Notable projects include providing financing to British motorbike firm Triumph and an $8bn commercial finance joint venture with Mubadala, based in Abu Dhabi.
GE Capital struggled during the economic downturn, but a recent resurgence saw the firm post net income of $1.1bn in the fourth quarter of 2010, compared with $99m in the same period of 2009.