Spanish builder ACS has bought a 5.8 percent stake in Hochtief to raise its holding in the German group to 66.54 percent.The shares were part of a placement by the Qatar Investment Authority (QIA), which divested its Hochtief stake of around 10 percent as part of a portfolio reshuffle. QIA placed 7 million shares in Hochtief for 77 euros apiece, fetching around 540 million euros ($614 million), it said in a statement. Morgan Stanley had offered the shares in an accelerated bookbuilding with a guidance of 76.50 euros to the market close of 81.78 euros. The QIA has been reviewing its investment strategy as a result of lower oil prices and following the appointment of a new chief executive in December. It sold a 1.1 percent stake in French construction group Vinci last week.