Startup funding is provided at various stages of a company's life cycle which begins with formulation of an idea. The source of funding can vary from a small retail individual investor using a crowdfunding platform, an accredited angel investor or a corporate venture capital round of financing. The current research has used bibliometric analysis to study a total of 2,644 articles over three decades (1989-2021) covering all the three main sources of start up financing--equity crowdfunding, angel investing and venture capital. The study has used Web of Science database to present the existing research trends, performance of authors, top journals, prominent existing themes as well as emerging future research areas in the field of equity crowdfunding, angel investing and venture capital. Emerging fields of study are venture capital determinants, decision making collaboration, regulations in the public markets. The emerging fields in crowdfunding are crowdfunding and networking, sustainable entrepreneurship and in the field of angel investing, relevant emerging themes include syndication and investment criteria of angel investment, decision making and impact of internal and global environment. [ABSTRACT FROM AUTHOR]