How does common ownership affect creative destruction? What are the underlying mechanisms? Do the effects of increased common ownership vary among different customer segments? Using product-level data, we show that, on average, firms with greater common ownership introduce new products at a faster rate and discontinue existing products at a similar pace. The observed economic impacts intensify over time, reflecting the gradual nature of knowledge spillovers and the learning curve. Subsequent to an increase in common ownership, portfolio firms tend to both add and drop products that are dissimilar to those of their rival firms, with the net effect of decreasing between-firm product dissimilarity. We also find that the effects are more relevant for product modules with greater technological likeness, lower barriers to market entry, and greater numbers of product market players. Product variety is substantially greater in product lines catering to higher-income households. Overall, the result highlights the procompetitive effects of increased common ownership.