Yes private organisations can participate as project partner. No restriction in terms of the company size, however the following should apply:
• they cannot be Lead Partner
• they have a legal personality
• they are not financed, for the most part, by the state, regional or local authorities, or other bodies governed by public law; or are not subject to management supervision by those bodies; or not having an administrative, managerial or supervisory board, more than half of whose members are appointed by the State, regional or local authorities, or by other bodies governed by public law
• if they are located in an IPA country, they should be non-profit.