Before the 1980s, employees' pensions in many private enterprises in the United States were paid in full by employers. Especially in enterprises with strong trade unions, employers are forced to pay various benefits for retired workers. Although this retirement benefit is beneficial to employees, it increases the economic burden of employers and is not conducive to the operation and development of enterprises. 1978, Item K added in Article 40 1 of the Internal Revenue Law of the United States stipulates that different types of employers, such as government agencies, enterprises and non-profit organizations, can enjoy tax preferences when establishing accumulated pension accounts for employees. According to this clause, more and more American enterprises choose the way that employers and employees jointly contribute and jointly establish retirement benefits. Therefore, American enterprise annuity plan is also called 40 1K plan.
At present, 40 1K plan has become the first choice for many employers in the United States to supplement the old-age security system for enterprises. According to the data of the American Association of Investment Companies, as of the second quarter of 20 13, the balance of assets in the 40 1K plan account reached 3.79 trillion US dollars, equivalent to about 22.9% of the GDP of the United States that year.