Which of the following is not the source of social insurance funds? The answer is social donation.

The sources of social insurance funds mainly include unit contributions, financial subsidies and individual contributions. Among them, unit payment means that enterprises and institutions deduct a certain amount from employees' wages in accordance with the prescribed proportion as social insurance premiums and pay them to the social insurance fund. Financial subsidy means that the government provides financial support to the social insurance fund according to needs to ensure the normal operation of the social insurance system.

Personal payment means that individuals deduct a certain amount from their wages as social insurance premiums in accordance with the prescribed proportion and pay them to the social insurance fund. However, social donations are not the source of social insurance funds. Social donation refers to the voluntary donation from all walks of life to the social insurance fund to support the development of social insurance. Although social donation can increase funds for social insurance funds, it is not the main source of social insurance funds, but an additional source of funds.

The main functions of the social insurance fund:

1. Social risk sharing: Social insurance funds share the risks of individual and unit contributions through centralized collection and management. When the insured faces risks such as unemployment, illness, work injury and maternity, the social insurance fund can provide corresponding economic compensation and welfare benefits to reduce the burden on individuals and families.

2. Construction of social security system: Social insurance fund is an important part of social security system, which provides support for the operation of social security system by raising and managing funds. Social insurance funds can be used to pay various social insurance benefits, including pension, medical expenses, unemployment benefits, industrial injury compensation, etc. To ensure that the insured can obtain corresponding social security under certain circumstances.

3. Social stability and fairness: The existence and operation of social insurance funds help to maintain social stability and fairness. Through the social insurance system, we can reduce social inequality and improve social equity. The use of social insurance funds can help vulnerable groups to obtain basic social security and reduce social instability.