Listed below are some provisions that are often contained in bond indentures:

1.	Fixed assets may be used as security.
2.	The bond may be subordinated to other classes of debt.
3.	The bond may be made convertible.
4.	The bond may have a sinking fund.
5.	The bond may have a call provision.
6.	The bond may have restrictive covenants in its indenture.

Which of the above provisions, each viewed alone, would tend to reduce the yield to maturity investors would otherwise require on a newly issued bond?