Definition of Shadow Stock
First, a public company may create a stock that strips out the market wide movements for the purpose of rewarding managers. That is, the management might have done a great job - but the traded stock plummets because the market as a whole plummets. A second interpretation of shadow stock is a phantom stock that is created by a private company (i.e. that does not have stock traded either on exchange or over the counter) again for the purpose of performance evaluation and rewards.