As far as the real reasons go, it's question of power.u00a0 Justifications are easily to find, because they're often false.Personal returns are not.u00a0 That's why politicians release their tax returns.u00a0 The reason is privacy.Charity/Non-profit returns might be.u00a0 I've seen Form 990 for some of them.u00a0 Churches and related organizations are exempt.u00a0 The reason might be to help the groups that rate charities.I've never read that corporate returns are available.u00a0 I'd expect them to be important to financial analysts, if they could be seen.u00a0 The reason is probably privacy.