Shanghai comprehensive insurance can be merged with social security period.

Legal analysis: Cannot merge. Take Shanghai as an example. When men reach the age of 60 and women reach the age of 50, migrant workers can cash their old-age subsidy certificates with their identity certificates, insurance certificates and other materials to relevant insurance companies or agreed institutions.

Legal basis: Interim Measures of Shanghai Municipality on Comprehensive Insurance for Foreign Employees.

Article 8 Employers and migrant workers without units shall pay comprehensive insurance premiums to the municipal migrant workers' employment management institution on a monthly basis from the month when they go through the registration formalities for comprehensive insurance.

Article 9 The base for employers to pay comprehensive insurance premiums is 60% of the average monthly salary of employees in the whole city in the previous year multiplied by the total number of foreign employees. The base of comprehensive insurance premium paid by foreign employees without units is 60% of the average monthly salary of employees in this city last year. Employers and foreign employees without units shall pay the comprehensive insurance premium according to the proportion of 12.5% of the payment base. Among them, the contribution rate of foreign construction enterprises is 5.5%.