Saudi Arabia’s 86-year-old king appointed his son, Crown Prince Mohammed bin Salman, to replace him as prime minister, continuing a gradual transfer of power in the world’s largest oil exporter. Already de facto ruler of Saudi Arabia, the appointment formalises Prince Mohammed as leader of the kingdom’s government. Known by his initials MBS, the crown prince, 37, already oversaw many of Saudi Arabia’s major portfolios, including oil, defence, economic policy and internal security – while his father King Salman bin Abdulaziz remains head of state. The royal decree on Tuesday did not give a reason for the move. The king will continue to chair cabinet meetings he attends, state-run news agency SPA said. The king spent a week in hospital in May for medical examinations and treatments, SPA reported at the time. A separate statement named one of the king’s other sons, Prince Khalid Bin Salman, to defence minister and reaffirmed all the other senior ministers in their posts. Will Biden’s fist-bump with Saudi’s MBS dent his image as rights defender? Heir to the throne since pushing aside an older cousin in 2017, MBS has steadily concentrated authority in his hands, detaining potential opponents and overturning the decades-old tradition of balancing power between branches of the royal family. That means that moving MBS to the position of prime minister is unlikely to be a precursor to any major policy shifts, said Jon Alterman, director of the Middle East Programme at the Centre for Strategic and International Studies in Washington. “This move codifies the status quo, in which he is driving the ministers’ agendas and coordinating between them,” Alterman said. “It may also have an international aspect in formally making him head of government, rather than a head of state-in-waiting.” Prince Mohammed has pushed forward with a sweeping economic transition programme in the Group of 20 nation. Earlier this year, he hosted US President Joe Biden in the kingdom, turning the page on years of frictions over the killing of Saudi columnist Jamal Khashoggi in Istanbul in 2018 by Saudi agents.