If the business is already operational, it will likely be classified as an existing business, which has its own set of requirements concerning job creation, etc.
This is addressed at part IV.B of the May 30, 2013, EB-5 Adjudications Policy Memo found at: http://www.uscis.gov/USCIS/Laws/Memoranda/2013/May/EB-5%20Adjudications%20PM%20(Approved%20as%20final%205-30-13).pdf staring at the bottom of page 8. [You probably have to cut and paste that URL into your browser.]
The goal of receiving personal investment funds from the foreign national investor and placing these funds into an existing U.S. corporation will require EB5 compliance. That is, the EB5 rules and policies will require the new personal investment funds to create additional employment for full-time employees who are U.S. citizens or U.S. permanent residents.