Under MOM legislation, a security bond is a binding pledge to pay the Singapore government up to $5,000 if you break the law or the conditions governing the employment of a helper. You need a bond for every helper you employ, unless she is a Malaysian. Helpers are not allowed to pay for the bond.
The bond is in the form of a banker’s or insurer’s guarantee. If you purchase NTUC Income insurance, the bond is included in it. If the bond is forfeited (any amount up to $5,000), the cost will then be transferred to you. Please note that it is very rare for the security bond to be forfeited.
You can find out more information here.