Alberta Investment Management Corp (AIMCo) has agreed to invest US$500 million in the acquisition of Swiss insurer Allied World Assurance Co Holdings AG by Fairfax Financial Holdings Ltd. Fairfax, a Canadian financial holding company, announced the proposed buy of Allied World for US$4.9 billion in December. The cash-and-stock transaction is expected to close in the second quarter. AIMCo’s investment will give it a stake in the company of about 10 percent. Allied World is a provider of property, casualty and specialty insurance and reinsurance solutions.