The emergence of new generations of digital technologies has presented firms with important strategic opportunities at the corporate level. This study investigates the digital transformation - unrelated diversification link and theorises the role of industry shakeout and the performance expectation gap in said relationship. Our analysis based on the data of China's A-share listed manufacturing firms from 2015 to 2020 shows that: 1) the degree of firms' digital transformation is positively correlated to the degree of their unrelated diversification; 2) industry shakeout positively moderates the above relationship, i.e., in industries with a higher degree of shakeout, the positive digital transformation-unrelated diversification link is more pronounced; 3) the performance expectation gap negatively moderates the digital transformation-unrelated diversification link, i.e., the greater the performance expectation gap, the weaker the positive correlation between firms' digital transformation and their unrelated diversification.