Certificate of Deposits (CDs) are considered the least liquid of these options.
Liquidity refers to the ease that the savings account can be converted to cash. Both money market and savings account both give you access to your money immediately (with certain withdrawal limits). Savings bonds are government issued and usually have a redemption maturity period of 6 months or more.
CDs are federally guaranteed savings account, but you are unable to access the money until the end of the maturity period which is usually 1 year to 5 years.
