The U.K. Financial Reporting Council (FRC) has launched an investigation into MacIntyre Hudson’s audit of collapsed construction company ISG Limited, which abruptly entered administration in September, laying off 2,200 workers.

The FRC said in a press release Tuesday the probe centers around the firm’s consolidated financial statements for the year ended December 31, 2022. In September, the U.K. Insolvency Service announced a group of eight ISG companies entered administration. At the time, ISG was one of the biggest construction companies in the U.K. with responsibility for more than 1 billion pounds of government contracts.