Co-operatization of large companies

This is a possible solution to the problems of corporate unaccountability.

Summary
All corporations above a certain should be co-operatively owned by the public, who would then receive:
 * quarterly profit dividends
 * voting rights in board elections

Gradation
This wouldn't have to be a hard line; the level of public ownership chould increase in a progression something like this, as the reach of the company's economic and ecological impacts increase:
 * workers
 * customers
 * neighborhood / community (where the company operates and does business)
 * town / county
 * state
 * nation(s)

Roughly, anyone who is measurably affected by the company's operations should have an ownership stake. If possible, stake size should be proportional to the degree of affectedness.