The parliament of Kazakhstan has approved legislative amendments banning foreigners from holding more than 49% ownership of the country’s airlines, Kazakhstan Today newswire reports.

The amendments are being introduced as part of preparing flag carrier Air Astana for privatization. Currently, 49% of the airline is owned by British company BAE Systems, with the remaining 51% controlled by Samruk Kazyna, the Kazakh state-run welfare fund.

The ban effectively enforces an earlier requirement for at least 51% of Air Astana to remain in the hands of Kazakh shareholders. The carrier’s privatization is expected to take the form of the initial (IPO) and secondary (SPO) public offerings. According to the latest news reports by the Kazakh prime minister’s press service, the release of Air Astana’s shares onto the private market is set for 2019-20.

Berik Beysengaliev, Samruk Kazyna’s managing director for asset optimization, announced in early March that the fund was planning to sell 25% of Air Astana. A similar amount of shares is to be sold by BAE Systems.

The 51% national ownership rule for carriers exists in many countries. Athough this figure is not explicitly mentioned in any documents, it allows for the effective fullfilment of international air agreements on air travel, which read that airlines are to be controlled by their respective states.