In the United States, a 401(k) is a way to save for retirement through the company you work for. You put part of your pay into a special account, often before tax, and many companies add a little extra if you join — that extra is called a match. The name comes from a line in US tax law, section 401(k). Though actually, it is not a government pension cheque, and it is not something you get automatically in Taiwan. The money can go up or down with the market, so it is savings-and-investment, not a guaranteed monthly pay-out. Informal writing often drops the brackets and says 401K.