grey market

noun

1. See black market
   a system involving the secret but not illegal sale of goods at excessive prices Compare black market
2. stock exchange a market in the shares of a new issue, in which market makers deal with investors who have applied for shares but not yet received an allotment
3. the market for goods and services created by older people with a comfortable disposable income and increased opportunities for spending it

Example Sentences

It isn't that I think that governments will actually make it completely impossible to use your grey market currency.

From The Daily Beast