If employees get a salary increase in May, can the base of social security be adjusted? How to adjust

It cannot be adjusted. The social security payment base is determined according to the employee's salary in the previous year, and 201.4-2012.3 is a cycle. Only one standard (in one company) can be implemented during the period, unless the employee leaves the new company, the new salary standard shall prevail when reporting. If the salary is adjusted in May, it will be reflected when the salary is declared next year.