KUALA LUMPUR (Reuters) – The President and Chief Executive Officer of Malaysia’s Petroliam Nasional Bhd, Wan Zulkiflee Wan Ariffin, is expected to announce his resignation from the company soon, state media Bernama reported on Saturday, citing unidentified sources.

Bernama said Wan Zulkiflee, who has lead the state-owned firm for five years, will be succeeded by an internal candidate.

In a statement, Petronas, as the company is known, declined to comment on “market rumour or speculation”.

“Official announcements, if any, will be made at the appropriate time,” the company said in an email response to Reuters.

Wan Zulkiflee, who joined Petronas [PETR.UL] in 1983 as a process engineer, worked his way up through the ranks to CEO, a prime ministerial appointment.

He took over in 2015 and lead the company through a period of tumultuous oil prices. Benchmark Brent crude slipped to under $30 a barrel in 2016, then rose to over $85 by 2018, followed by a historic crash in April this year to below $20 after the coronavirus outbreak slashed demand.

Wan Zulkiflee also championed an ambitious $27 billion oil refinery and petrochemical plant joint venture with state-owned Saudi Arabian oil company Saudi Aramco located in the southern state of Johor.

Petronas is the sole manager of Malaysia’s oil and gas reserves, and a key source of revenue to state coffers.

It said in February it would pay the Malaysian government, its only shareholder, a regular dividend of 24 billion ringgit ($5.5 billion).