Two adverts from HSBC publicising its role in the green transition have been banned for omitting information about its own contribution to carbon dioxide and greenhouse gas emissions.
The posters, seen on bus stops in Bristol and London in October 2021, showed images of waves crashing on a shore and tree growth rings with the phrase: "Climate change doesn't do borders."
They detailed that HSBC aimed to provide up to £880bn ($1trn) in financing and investment globally to help its clients transition to net zero, and helping to plant two million trees in the UK to lock in 1.25 million tonnes of carbon over their lifetime.
Some 45 people complained to the Advertising Standards Authority (ASA), with some arguing that they were misleading because they failed to mention significant information about HSBC's contribution to the climate crisis.
HSBC UK said the financing of greenhouse gas-emitting industries was required during the transition to net zero, and so their continued financing of those industries was not in conflict with the aims of a transition to net zero.
The ASA said the basis of environmental claims must be clear and that unqualified claims could mislead if they omitted significant information.
"We concluded that the ads omitted material information and were therefore misleading," the ASA said in a ruling.
The regulator ruled that "future marketing communications featuring environmental claims were adequately qualified and did not omit material information about its contribution to carbon dioxide and greenhouse gas emissions".
As a business, HSBC said it aimed for a 34% reduction in absolute oil and gas financed emissions and a 75% reduction in financed emissions intensity for the power and utilities sector by 2030.
They planned to phase out their financing of thermal coal by 2030 in the European Union and Organisation for Economic Co-operation and Development (OECD) countries, and by 2040 in the rest of the world.
Campaigners hope the ruling will set a precedent for other adverts from the finance sector.
Robbie Gillett from campaign group Adfree Cities, who led the complaint, called it a "significant moment in the fight to prevent banks from greenwashing their image".
"HSBC can no longer ply us with ads pretending they are green while continuing to bankroll climate breakdown in the background," he said.
A HSBC UK spokesperson said: "The financial sector has a responsibility to communicate its role in the low carbon transition to raise public awareness and engage its customers, so we will consider how best to do this as we deliver our ambitious net zero commitments."