Oak, a new private client, corporate services and fund administration group, has acquired International Administration Group (IAG). : Oak, a new private client, corporate services and fund administration group, has acquired International Administration Group (IAG). Founded in 2000 by Mark Woodall and Alison Simpson, IAG is a specialist fund administration business headquartered in Guernsey with a team of 43 people. IAG delivers bespoke fund administration and depositary services to private equity, open-ended, listed and alternative asset fund structures and will become the centre of fund expertise within the Oak business.