72 Pa. Stat. § 9150
The department may, for reasonable cause, extend the time for payment of any part of the inheritance tax and may, if deemed necessary for the protection of the interest of this Commonwealth, require the transferee in present possession or, if a trust is involved, the trustee to file a bond in the name of the Commonwealth with sufficient surety, in an amount not exceeding twice the tax computed when the bond is given at the highest rate possible in the specific contingencies involved (reduced by the amount of any partial payment made) and conditioned for the payment of the tax at such postponed due date, together with interest from the due date to the payment date. No bond shall be required under this section if the trustee or one of the trustees is a bank and trust company or a trust company incorporated in this Commonwealth or a national banking association having its principal office in this Commonwealth. The bond required shall be filed in the office of the register.
72 P.S. § 9150