In March 2018, NEX announced an approach by CME Group further to a proposed acquisition. CME Group offered £3.8bn in a cash-and-share deal, valuing Spencer's stake at approximately £668m. By the time the deal was completed in November 2018, Spencer's stake had grown to over £700m, half of which he received in cash, raising his net worth to over £1bn. As a listed company, NEX's total shareholder return was close to 6,000 per cent. Spencer serves as a CME Group Board Member and Special Advisor.