(a) General rule: Perfection by filing. Except as otherwise provided in subsection (b) of this section and section 9-312(b), a financing statement must be filed to perfect all security interests and agricultural liens.
(b) Exceptions: Filing not necessary. The filing of a financing statement is not necessary to perfect a security interest:
(1) That is perfected under section 9-308(d), (e), (f) or (g);
(2) That is perfected under section 9-309 when it attaches;
(3) In property subject to a statute, regulation or treaty described in section 9-311(a);
(4) In goods in possession of a bailee which is perfected under section 9-312(d)(1) or (2);
(5) In certificated securities, documents, goods or instruments which is perfected without filing, control, or possession under section 9-312(e), (f) or (g);
(6) In collateral in the secured party's possession under section 9-313;
(7) In a certificated security which is perfected by delivery of the security certificate to the secured party under section 9-313;
(8) In deposit accounts, electronic chattel paper, electronic documents, investment property or letter-of-credit rights which is perfected by control under section 9-314;
(9) In proceeds which is perfected under section 9-315; or
(10) That is perfected under section 9-316.
(c) Assignment of perfected security interest. If a secured party assigns a perfected security interest or agricultural lien, a filing under this article is not required to continue the perfected status of the security interest against creditors of and transferees from the original debtor.