Definition of Institutional Investor:
1. A bank, savings and loan association, insurance company or registered investment company.
2. An investment adviser registered either with the SEC Under Section 203 of the Investment Advisers Act or with a state securities commission (or any agency or office performing like functions).
3. Any other person (whether a natural person, corporation, partnership, trust or otherwise) with total assets of at least $50 million.
Source: https://www.finra.org/rules-guidance/rulebooks/finra-rules/4512