According to different organizational forms, it can be divided into corporate funds and contractual funds. A fund is established by issuing fund shares to establish an investment fund company, which is usually called a corporate fund; The establishment of fund managers, fund custodians and investors through fund contracts is usually called contractual funds. China's securities investment funds are all contractual funds. Contract fund, also known as unit trust fund, refers to a fund management company jointly funded by specialized investment institutions (banks and enterprises). As the principal, the fund management company and the trustee jointly issue the beneficiary certificate-"fund share holding certificate" to raise social idle funds.