In its simplest form, a 401(k) plan looks like a collection of individual savings accounts subject to a bunch of rules. Each participant's individual account is credited with employee and any employer contributions and adjusted for investment earnings and losses. Any benefits and expenses paid are deducted from the account. This chapter discusses some general 401(k) plan rules and ways to take full advantage of them. It also discusses aspects of 401(k) plans critical to employing the day trading strategy that you can use to juice your returns in an uncertain market.