http://finance.zacks.com/tax-consequences-revocable-irrevocable-trusts-2838.html
Revocable and irrevocable trusts are treated quite differently under U.S. tax law. The main reason for this disparity is that the assets of a revocable trust are considered the property of the grantor, while an irrevocable trust is treated as an independent legal entity that owns its assets. Creating a trust may carry unexpected tax consequences, some of which may be unfavorable.