Section 409.310 - When filing required to perfect security interest or agricultural lien; security interests and agricultural liens to which filing provisions do not apply(1) GENERAL RULE: PERFECTION BY FILING. Except as otherwise provided in sub. (2) and s. 409.312(2), a financing statement must be filed to perfect all security interests and agricultural liens.(2) EXCEPTIONS: FILING NOT NECESSARY. The filing of a financing statement is not necessary to perfect a security interest:(a) That is perfected under s. 409.308(4), (5), (6), or (7);(b) That is perfected under s. 409.309 when it attaches;(c) In property subject to a statute, regulation, or treaty described in s. 409.311(1);(d) In goods in possession of a bailee which is perfected under s. 409.312(4) (a) or (b);(e) In certificated securities, documents, goods, or instruments which is perfected without filing, control, or possession under s. 409.312(5), (6), or (7);(f) In collateral in the secured party's possession under s. 409.313;(g) In a certificated security which is perfected by delivery of the security certificate to the secured party under s. 409.313;(h) In deposit accounts, electronic chattel paper, electronic documents, investment property, or letter-of-credit rights which is perfected by control under s. 409.314;(i) In proceeds which is perfected under s. 409.315; or(j) That is perfected under s. 409.316.(3) ASSIGNMENT OF PERFECTED SECURITY INTEREST. If a secured party assigns a perfected security interest or agricultural lien, a filing under this chapter is not required to continue the perfected status of the security interest against creditors of and transferees from the original debtor.