The purpose of this paper is to determine existing models of startup funding depending on the accepted model of fundraising, types of startup investors, to systematize the approaches and to define the existing forms of investing in accordance with the features of cooperation with business incubators, business accelerators, business angels, venture funds and crowdfunding campaigns with the aim of a further grounding of ways of improving of financing and development of starts in Ukraine on the basis of generalization of the domestic and foreign experience in the sphere of SMB investing. The objectives stated in this paper are solved with the help of such general scientific and specialized research methods: analysis and synthesis, systematizing and generalizing, dialectical approach. We systematized theoretical principles and practical approaches of the startup fundraising concerning specification of models and sources of startup financing in the context of cooperation with main startup investors. We disclosed peculiar features and distinctions of sources of funding and principles of their engaging depending on investing needs and startup investors at different stages of development of projects. The main results of the work can be used by the subjects of the entrepreneurship in the spheres of venture and other forms of traditional or alternative investment.