On 9 January 2006 Pearson announced the purchase of 1,130,739 shares in Interactive Data Corporation (IDC) for $21.67 per share in cash. This purchase brings Pearson's total holding in IDC to almost 62%. On 23 January 2006 Pearson announced the acquisition of Promissor, a leading professional testing business from Houghton Mifflin Company for $42m in cash.