Qantas Airways Ltd. Chief Executive Officer Alan Joyce sold A$16.9 million ($11.3 million) of shares in the airline, offloading the bulk of his holdings as he prepares to retire after 15 years at the helm.

Joyce sold 2.5 million shares at A$6.75 apiece on June 1, a regulatory filing showed. Qantas shares fell 4.1% to A$6.35 on Tuesday.

Joyce, 56, is due to hand over to Qantas Chief Financial Officer Vanessa Hudson in November. The filing indicates he sold his shares about 48 hours after fronting bullish investor-day presentations in Sydney that led to a three-day run of stock gains.

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According to the Australian Financial Review, Joyce executed the sale after buying a penthouse in the city overlooking the Sydney Opera House for A$9 million. He had bought the shares for A$1.50 each in 2012, the newspaper said.

Joyce still owns 228,924 shares in the Australian airline, the filing showed. They’re currently worth about A$1.5 million.