Macquarie Infrastructure Group's plan to shield its best assets from its more heavily indebted motorways got a big boost this week when a fee rise was flagged for its biggest toll road. Starting from February 1, Toronto's 407 ETR will increase peak-hour tolls on its busiest segments by 8 per cent. MIG will group its 30 per cent stake in the 407 and its 25 per cent share of Sydney's WestLink M7 in a new company called Intoll while ring-fencing its seven remaining motorways, which have a combined $8.8 billion of debt, in a separate company. MIG's shares have climbed 5 per cent since the beginning of December. But expectations are high that Intoll will not be around for long, with potential buyers such as the Canada Pension Plan likely to snap it up for its stable earnings.