Annuity originated in a country with relatively developed free market economy, and it is a kind of employee welfare plan voluntarily established by enterprise employers. Namely the pension provided by the enterprise pension plan. Its essence is a part of employees' labor remuneration or a part of employees' sharing of enterprise profits in the form of deferred payment. Annuity is called annuity abroad, which is a series of regular or irregular cash inflows or outflows. Annual amount refers to the amount of each income and expenditure. Annuity period refers to the time interval between two adjacent years. Annuity period refers to the duration of the whole annuity income and expenditure, and there are usually several periods. Participating in the annuity plan is a good investment arrangement, and the financial institutions that provide annuity contracts are generally insurance companies and treasury bonds. For example, if you buy endowment insurance, you actually participate in an annuity contract. The final value of an annuity includes the sum of the principal deposited every year and the interest generated by the principal deposited every year. However, the interest generated by these principal deposits varies with time. The classification of annuities can be divided into ordinary annuity (deferred annuity), immediate annuity (annuity in advance, early annuity), deferred annuity (deferred annuity), perpetual annuity, etc. 1, ordinary annuity ordinary annuity refers to a series of payments received and paid in equal amount at the end of each period from the first period, also known as post-paid annuity. 2. Pay-as-you-go annuity refers to a series of money received and paid at the beginning of each period within a certain period of time from the first period, also known as pay-as-you-go annuity. The only difference between an instant annuity and ordinary annuity is the payment time. 3. Deferred annuity Deferred annuity refers to a series of equal income and expenditure after several periods (M) instead of the first period. It is a special form of ordinary annuity. 4. Permanent annuity refers to a special annuity that is received and paid in equal amount indefinitely. It is a special form of ordinary annuity, that is, ordinary annuity whose term tends to be infinite. Definition of annuity Enterprise annuity refers to a supplementary pension system established by enterprises under the guidance of national policies and according to their own economic strength and situation, in addition to compulsory public pension or national pension, to provide a certain degree of retirement income protection for enterprise employees. Enterprise annuity fund refers to the supplementary endowment insurance fund for enterprises formed according to the funds raised by enterprise annuity plan and the income from its investment and operation. The urban workers' old-age insurance system being perfected in China consists of three parts: basic old-age insurance, enterprise annuity and personal savings old-age insurance. Therefore, enterprise annuity is known as one of the important components of the "three pillars" of the old-age insurance system for urban employees. In countries with modern social insurance system, enterprise annuity has become a common supplementary pension plan for enterprises, also known as "enterprise annuity plan" or "occupational annuity plan", and has become an important part of the old-age insurance system in the host country. Personal annuity refers to a trust method in which employees withdraw a certain percentage of money from their wages every month during their work and deposit it in a trust bank. After retirement, the trust bank will allocate it to employees for personal use in stages. At present, it is more common abroad. The newly popularized individual supplementary savings pension in China belongs to this category. Variable personal annuity refers to the combination of annuity and variable life insurance developed to prevent inflation from affecting personal savings pension. Its cash value and annuity payment fluctuate with the investment situation. This is a major insurance in foreign countries and an important part of endowment insurance. At present, domestic endowment insurance is still in the category of basic endowment insurance, and there is no such variety.