Fidelity offers a wide variety of financial and investing services to individuals and businesses. When opening an investment account, Fidelity places whatever money you decide to start investing with in a core account.
Purpose of Core Account
The core account is a holding tank of sorts for un-invested cash. It is made up of initial investments, additional deposits, cash dividends and trade proceeds. Fidelity uses this core money when processing cash transactions such as security, mutual fund and check card purchases; ATM and check withdrawals; and bill payments. The default core account is Fidelity's FCASH account.
Fidelity provides the FCASH account so account holders can still make money off their core accounts. FCASH is interest-bearing, with an interest rate of 0.01 percent as of 2012. Account holders can also choose from two other core positions: a government money market fund or treasury money market fund. If the account holder wants to change his core position, he can do so by calling a Fidelity representative.