Ashurst is advising Canadian and Australian private equity firms Ontario Teachers' Pension Plan and Victorian Funds Management in their joint bid for Birmingham Airport Holdings. The two private equity firms have made an -unconditional offer for a 48.3 per cent stake in the Midlands airport -operator. The £420m offer was accepted by Macquarie- -Airport Group and Aer Rianta International, a subsidiary of the Dublin -Airport Authority, which are being advised by several firms, including Arthur Cox, Eversheds and -Linklaters. Airport Group -Investments, the investment arm for the Canadian-Australian outfit, will now open discussions with the seven West Midlands -district councils that maintain pre-emptive rights and hold a majority 49 per cent stake in -Birmingham Airports. There is a 90-day period for the councils to come to a decision on exercising these pre-emption rights.