Stuart Kirk resigned as global head of responsible investing at HSBC Global Asset Management, he announced in a LinkedIn post Thursday.
Mr. Kirk was named to the post in July 2021 after serving as global head of research and insights since January 2020.
He was suspended in May after making controversial remarks at a Miami conference, including that climate change is not a financial risk to worry about.
HSBC Asset Management executives issued statements that his views do not reflect the firm and that it regards climate change as a serious emergency.
In his LinkedIn message, Mr. Kirk said HSBC's conduct since then has been "unsustainable."
His next project involves creating "a whole new asset class" that he said will underline the central argument in his Miami speech: "that human ingenuity can and will overcome the challenges ahead, while at the same time offering huge investment opportunities," he said, promising an announcement later this year.
In the meantime, he pledged "to continue to prod with a sharp stick the nonsense, hypocrisy, sloppy logic and group-think inside the mainstream bubble of sustainable finance."
HSBC declined to comment on his resignation.