Set-aside contracts: The government can “set a contract aside” for any small business, or for a particular kind of small business. If this happens only small businesses with a particular kind of set-aside can bid
Sole-source: The government can directly award contracts (so no competition) to companies with certain set-asides
Sub-contracting: Large prime contractors are encouraged to sub-contract work to small businesses with set-asides
State contracts: Many states provide preferences for companies who are pursuing state contracts if they have a set-aside
Business support: There are state and federal programs to help small business entrepreneurs and entrepreneurs who are members of various groups.
Mentor protege: The Mentor Protege program allows more established vendors to create a special mentor-protege relationship with small businesses which allows the large to work more closely with that small business than they could ordinarily