Irrevocable trust is a trust that cannot be modified or terminated without the permission of the beneficiary. In most states, a trust will be deemed irrevocable unless the grantor specifies otherwise. Once the grantor has transferred assets into the trust, s/he has no rights of ownership to the assets and the trust. Irrevocable trusts are preferred because it removes all incidents of ownership, thereby effectively removing the trust’s assets from the grantor’s taxable estate. The grantor is also relieved of the tax liability on the income generated by the assets. This is the opposite of a “revocable trust”, which allows the grantor to modify the trust.