For unregistered investment companies, the report found that hedge funds to be the most vulnerable to money laundering. This was because of the relatively high liquidity of their structure and interests. Hedge funds have relatively short periods where money is kept locked up, and a hedge fund's structure makes them vulnerable because domestic hedge funds do not need to identify the source of their funding, and offshore hedge fund structures are complex and more likely to allow "anonymous" investments. The report notes that commodity pools are highly regulated and that private equity funds and venture capital funds are long term investments that provide little opportunity to redeem their investments. The report also noted that Real Estate Investment Trust (REITs) investments "to be illiquid because the investors have no right to redeem their interests and the REIT often restricts the transfer of interests to comply with other [Internal Revenue Code requirements".