buy up

verb3

1. •
   To buy the whole of; to purchase the entire stock of something.

   • The marshland was bought up by a housing company.
2. •
   To buy whatever is available of something.
3. •
   To buy off; to pay in blackmail money or similar.

   • Sir Leicester Dedlock, Baronet, it's for you to consider whether or not to buy this up. I should recommend, on the whole, it's being bought up myself; and I think it may be bought pretty cheap. — 1852