In July 2017, he urged Trump to block the sale of the Chicago Stock Exchange to Chinese investors, arguing that China's "rejection of fundamental free-market norms and property rights of private citizens makes me strongly doubt whether an Exchange operating under the direct control of a Chinese entity can be trusted to 'self-regulate' now and in the future." He also expressed concern "that the challenges plaguing the Chinese market – lack of transparency, currency manipulation, etc. – will bleed into the Chicago Stock Exchange and adversely impact financial markets across the country."