1. "Pension funds", which include stuff like TIAA-CREF, who administer 401(k)-like plans for tax-exempt organizations. Those are definitionally fully funded because the annuities that retirees receive are only based on the money they put in over time.
2. "Pensions" as in the old-school corporate-owned "you work for us for n years and then we give you an annuity for the rest of your life, based on a percentage of ending salary." Those have a lot of problems with funding, for a load of reasons including life expectancy, and because bankruptcy relieves companies of a lot of those obligations.
Either way, a shareholder owning a comparatively tiny amount of stock has neither a duty nor the impetus to align their interests with that of the corporation in which they hold stock.