Price discrimination boosts competition, lowers prices, and benefits consumers.
Antitrust laws usually prevent companies from charging different prices to competing buyers. But when a manufacturer owns some of its rival's shares and both buy materials from a monopolist, lower prices are given to the one with the shares. This leads to more production from that company, reducing the negative effects of shareholding. As a result, there is more output, lower prices for consumers, and overall better welfare for everyone involved compared to charging the same price to both companies.