Table 2.

Variable description.

Variable description	Definition
Explained variables
Risky financial assets	Financial assets other than cash and bank savings deposits are considered as risky financial assets. According to the CHFS questionnaire survey, if a household holds any form of risky financial assets, it is coded as 1; otherwise, it is coded as 0.
Willingness	Willingness to invest in risky financial assets. Using the investment risk preference question designed in the CHFS questionnaire: If you had a sum of money to invest, which investment project would you be most willing to choose? The answers include: 1. high risk, high return project; 2. slightly high risk, slightly high return project; 3. average risk, average return project; 4. slightly low risk, slightly low return project, and 5. unwilling to take any risk. According to the respondents’ answers to the above questions, when the respondents choose 1, 2, 3, or 4, a value of 1 is assigned, indicating that the residents are willing to invest in risky financial assets; when the respondents choose 5, a value of 0 is assigned, indicating that the residents are not willing to invest in any form of risky financial assets.
Explanatory variables
Social medical insurance	Whether to participate in social medical insurance. 1 if participating, 0 if not participating
Health risks	The health risk was measured by whether the physical condition was poor, with poor physical condition, health risk of 1, and good physical condition, health risk of 0. With the help of the question in the CHFS questionnaire: How is the physical condition now compared to the peers? The responses were designed as 1. very good; 2. good; 3. average; 4. bad; and 5. very bad, where respondents who chose 3, 4, and 5 were in poor physical condition and assigned a value of 1, and respondents who chose 1 and 2 were in good health and assigned a value of 0.
Household health risks *social medical insurance	Interaction term between health risk and social medical insurance. The number of people with poor health status in the household is calculated as a unit, which is used to measure and express the magnitude of health risk that exists in the household, and then multiplied with whether or not to participate in social medical insurance
Household health risk rate	Household health risk rate = number of people in poor physical condition in the household/number of people in the household
Household social medical insurance participation rate	Family social medical insurance participation rate = number of family participants in social medical insurance / number of family members
Commercial medical insurance	Whether to participate in commercial medical insurance.1 if participating, 0 if not participating
Household health risks *commercial medical insurance	Interaction term between health risk and commercial medical insurance. The number of people with poor health status in the household is calculated as a unit, which is used to measure and express the magnitude of health risk that exists in the household, and then multiplied with whether or not to participate in commercial medical insurance
Risky assets ratio	Risky assets ratio = risk assets/household total assets
Control variables
Number	Number of family members. This is the whole number, which is a count of the number of family members
ln_total income	This is a continuous variable, taking the logarithm of total household income
Education	Years of education. According to the CHFS questionnaire, the education level of household members is: 1. never attended school; 2. elementary school; 3. junior high school; 4. high school; 5. junior high school/vocational high school; 6. college/vocational high school; 7. university undergraduate 8. master’s degree 9. doctoral degree 0 for no school; 6 for elementary school; 9 for junior high school;12 for high school/junior college/vocational high school; 15 for college/vocational high school; 16 for university undergraduate; 18 for master’s degree; 22 for doctoral degree
Age	Age squared
Ln_medical expenses	This is the continuous variable, where the household’s annual medical expenditure
Gender	Male = 0, Female = 1
Social pension insurance	Types of social pension insurance. In the CHFS data, the specific questions are: which of the following social pension insurance is participated in? 5 = Organization and institution pension/retirement pension; 4 = Basic pension insurance for urban workers (urban employment insurance, generally paid monthly); 3 = New rural social pension insurance (new rural insurance, paid annually); 2 = Urban residents’ social pension insurance (urban residence insurance, paid annually); 1 = Unified urban and rural residents’ social pension insurance (annual payment); and 0 is not participated in social pension insurance.