1 and 40 1k plans are also called 40 1K clauses. The 40 1k plan began in the early 1980s. It is a fully funded old-age insurance system jointly established by employees and employers, with reference to the newly added Article 400th in the US Internal Revenue Law. 1979 is recognized by law, and the detailed rules for implementation are added in 198 1. It developed rapidly in the 1990s, gradually replacing the traditional social security system and becoming the first choice for many employers in the United States. Suitable for private profit-making companies.

2. 40 1K in the United States is an enterprise annuity. American pensions are divided into two parts. Part of it is social insurance at the national level, which is equivalent to China's old-age insurance, and guarantees the basic old-age life of employed people after retirement. The other part is the enterprise's pension plan, and the 40 1K plan is only an important part, which is equivalent to the enterprise annuity plan in China. It is not rigorous to equate the 40 1K plan in the United States with the pension in China.

3. Social insurance tax, also known as "payroll tax", is a tax levied by the US federal government to raise funds for the social security system. The American social security system sprouted during the Great Depression in 1930s, and began with the 1935 Social Security Act during Roosevelt's New Deal.

4. The social insurance tax stipulates the maximum amount with tax basis, and the wages and salaries exceeding the limit are not taxed. The upper limit is adjusted according to the annual consumer price index. In 1996, employers and employees are required to pay the social insurance tax with the tax rate of 7.65% for the part whose total salary is less than 62,700 dollars (6 1200 dollars). In addition, the employer and employees should pay the medical insurance tax for the elderly and the disabled at the rate of 1.45% respectively for all wages exceeding the above limit.

5. There are generally two ways to collect social insurance tax: one is to take source withholding; One is to declare and pay by yourself. The employee's tax payable is taxed by the employer according to the employee's taxable wages and salaries, withheld at the source, and declared and paid together with the employer's own tax payable every quarter. The federal insurance tax levied on self-employed individuals is basically similar, except that self-employed individuals have to pay all the taxes themselves. If the self-employed are both employees and self-employed, the federal insurance tax payable should be determined according to their employee status; If the total wages of taxpayers as employees do not exceed the maximum limit of tax basis, or the part below this limit, they shall be taxed as self-employed.