Remove limited liability as a concept: stop funding the extrinsic risks of large corporate actors. Don't shield stockholders from criminal and unethical acts committed in the organization's name. Watch the incentives change and only very small companies exist. Where necessary, big companies will be run VERY cautiously, as they should be.

EDIT: of course this would "economically devastating", at least to the present way of being, can you imagine the risk of being an officer in a large corporation or a stockholder? but maybe the economic advantages of reduced corruption and mega-corp inefficiency would soften the blow in the medium to long term?