Norwich Union was targeted by campaigners protesting against insurers who pursue environmentally damaging investment policies.
Friends of the Earth activists tried to present a dinghy to NU chairman George Paul at the company's Norwich headquarters, warning that its investments in polluting companies were contributing to rising sea levels.
NU declined to comment, claiming it had not seen FoE's report suggesting that the company has a poor environmental record.
But an NU spokeswoman said environmental issues were being addressed at the highest level of the company.
