BP chief executive officer Bernard Looney has resigned after less than four years on the job, the London-based oil producer announced Tuesday.

Looney took over as CEO of BP in 2020 after previously leading BP’s Upstream group, focused on exploration and production. The resignation of Looney is effective immediately. The company’s Chief Financial Officer Murray Auchincloss will serve as interim CEO, BP said.

The change comes as Looney informed the company that he was not “fully transparent in his previous disclosures” about relationships with colleagues prior to becoming CEO, BP said.

“The Company has strong values and the Board expects everyone at the Company to behave in accordance with those values. All leaders in particular are expected to act as role models and to exercise good judgement in a way that earns the trust of others,” BP said in a statement.

Previous investigations into Looney’s relationships with colleagues found no break of BP’s code of conduct, but new investigations are ongoing, the company said.

The news of the resignation was first reported by the Financial Times.

U.S.-traded shares of BP closed down 1.3% Tuesday after climbing as much as 2.9% earlier in the session.

When Looney was promoted to CEO, board chair Helge Lund praised the executive as the right choice to lead BP during a transitional era away from fossil fuels and toward renewables.

Looney took over the role near the beginning of the Covid-19 pandemic, which led to a sharp sell-off for energy stocks, including BP. The U.S.-traded shares of the company are roughly flat since January 2020.

The company’s most recent quarterly report showed a sharp drop in profit, as oil prices had declined since 2022. BP did however hike its dividend and authorize a stock buyback.

BP also faced pressure from activists and shareholders earlier this year after rolling back some of its emission reduction targets.

Looney told CNBC’s “Squawk Box” on Aug. 1 that the change in targets was due in part to energy security concerns that arose last year. He said the company had also increased its spending on renewables and was pursuing an “and, not or” strategy in connection with energy production sources.

“We believe that’s what the world needs, and we believe that’s what’s good for our shareholders,” Looney said.