Most passive investors nowadays are investing in index funds. In that case all three of your investors receive equivalent return as the index rebalances away from the failing company.
the impact is lessened, sure, but i shouldn't think the returns would be identical. the raiders try to sell their shares while the price is buoyed by the buyback program. the index funds wouldn't rebalance during that time because of that price buoy. at the point the buoy weakens, those index funds are stuck selling into the decline. a simplistic model with instant rebalancing and infinite liquidity would put their returns near half.
