Mich. Comp. Laws § 331.73

Sec. 43. Any pledge made by an authority shall be valid and binding from the time the pledge is made. The moneys or property so pledged and thereafter received by the authority shall immediately be subject to the lien of the pledge without any physical delivery thereof or further act. The lien of any such pledge shall be valid and binding as against all parties having claims of any kind in tort, contract or otherwise against the authority, irrespective of whether such parties have notice thereof. Neither the resolution nor any other instrument by which a pledge is created need be recorded.