Hello! I am currently studying the market for corporate control and the types of discounts that are usually applied when valuing companies. An interesting one is the holding discount, which is a company-level discount applied to conglomerates. The rationale for this discount is that diversifying at company level is seen as non-optimal for investors, since they can diversify at portfolio-level at lower costs. My question is, is this always true? I mean, my idea is that if you diversify with stocks you may be missing diversification at business level, and economies that you can obtain only by putting companies together in the "real life" and not in a portfolio. How would you model that?