Australia’s Foreign Investment Review Board (FIRB) has given its approval for Singapore Airlines (SIA) to increase its stake in Virgin Australia to 19.9 per cent. SIA will now purchase an additional 255.5 million shares at 48 Australian cents per share, worth a total of A$122.6m. SIA took a 10 per cent stake in Virgin Australia in late 2012. The next share purchase will add a further 9.9 per cent stake in the airline. The airline said the transaction should be completed by the end of next week.