A billionaire oligarch resigned as CEO of Russia's second-largest oil company after being sanctioned by the UK

• Russian billionaire Vagit Alekperov resigned as CEO of Lukoil on Thursday, following UK sanctions.
• Lukoil is the second-largest oil company in Russia and one of the world's largest oil producers.

Russian billionaire Vagit Alekperov has resigned as CEO of Lukoil — the second largest oil company in Russia.

The Thursday announcement comes a week after the UK sanctioned Alekperov under claims that he "continues to support the Government of Russia" by serving as a director within the country's energy sector. Alekperov joins a handful of Russian business leaders that have departed their firms following the invasion of Ukraine.

Alekperov, who Forbes estimates to be worth $18.6 billion, started his oil career as a rig worker in the Caspian Sea. By 1990, he was the Soviet Union's deputy minister of the oil and gas industry, according to the Lukoil website.

In 1991 — the same year the Soviet Union collapsed — Alekperov converted three government-owned oil fields into Lukoil, according to his bio on Forbes. Alekperov is currently ranked as Russia's eighth-richest person on the Bloomberg Billionaire Index.

The oligarch had, until recently, escaped personal sanctions. In a 2004 New York Times Magazine feature titled "The Triumph of the Quiet Tycoon," Alekperov is described as a man whose "unimpressiveness is calculated" and "behaves as if his greatest wish is to be ignored by the public."

''I can't afford to be indifferent to politics, but I don't have personal ambitions," Alekperov told the Times in 2004. "I have only one task connected with politics, to help the country and the company. I'm not close to Mr. Putin, but I treat him with great respect.''

On March 3, Lukoil posted a statement on its website calling for "fast resolution of the military conflict" in Ukraine.

"We fully support its resolution through negotiations, by diplomatic means," the statement reads. "The company is taking efforts to continue stable work in all countries and regions of its presence."