Section 344.15 - Requirements as to policy or bond(1) No policy or bond is effective under s. 344.14 unless issued by an insurer authorized to do an automobile liability or surety business in this state, except as provided in sub. (2), or unless the policy or bond is subject, if the accident has resulted in bodily injury or death, to a limit of not less than $25,000 because of bodily injury to or death of one person in any one accident and, subject to that limit for one person, to a limit of not less than $50,000 because of bodily injury to or death of 2 or more persons in any one accident and, if the accident has resulted in injury to or destruction of property, to a limit of not less than $10,000 because of injury to or destruction of property of others in any one accident.(2) A policy or bond with respect to a vehicle which was not registered in this state or was registered elsewhere at the time of the effective date of the policy or bond or the most recent renewal thereof may be effective under s. 344.14 even though not issued by an insurer authorized to do an automobile liability or surety business in this state if the policy or bond either meets the liability limits specified in sub. (1) or meets the liability limits of the equivalent law of the state in which issued and such limits are, in the judgment of the secretary, adequate to cover any damage or injury involved in the accident in question.(3) Where service of process is made on the secretary, the secretary shall forthwith mail by registered mail a copy of the process papers to the insurer at the address given. In all cases of such service, there shall be served 2 authenticated copies for the secretary and such additional number of authenticated copies as there are defendants so served in the action. One of the secretary's copies shall be retained for the secretary's record of service and the other copy shall be returned with proper certificate of service attached for filing in court as proof of service of the copies by having mailed them by registered mail to the defendants named therein. The service fee shall be $4 for each defendant so served.(4) After receipt of the report of an accident of the type specified in s. 344.12 , the secretary may forward to the insurer named therein, that portion of the report or other notice which pertains to an automobile liability policy or bond. The secretary shall assume that an automobile liability policy or bond as described in this section was in effect and applied to both the owner and operator with respect to the accident unless the insurer notifies the secretary otherwise within 30 days from the mailing to the insurer of that portion of the report or other notice pertaining to the automobile liability policy or bond. Upon receipt of notice from the insurer that an automobile liability policy or bond was in effect as to the owner only, the operator only or was not in effect as to either of them, the secretary shall within the remainder of the 90-day period specified in s. 344.13(3) require the owner or operator or both, whichever is applicable, to deposit security pursuant to this chapter. As respects permission to operate the vehicle, the insurer may correct the report or other notice only if it files with the secretary within the 30-day period specified in this subsection an affidavit signed by the owner stating that the operator did not have the owner's permission to operate the vehicle. Where the insurer's failure to notify the secretary within 30 days of a correction in that portion of the report or other notice pertaining to an automobile liability policy or bond is caused by fraud, the insurer shall notify the secretary of the correction within 30 days of the time the fraud is discovered.(5) Nothing in this chapter shall be construed to impose any obligation not otherwise assumed by the insurer in its automobile liability policy or bond except that if no correction is made in the report or other notice within 30 days after it is mailed to the insurer, the insurer, except in case of fraud, whenever such fraud may occur, is estopped from using as a defense to its liability the insured's failure to give permission to the operator or a violation of the purposes of use specified in the automobile liability policy or bond or the use of the vehicle beyond agreed geographical limits.1975 c. 55; 1977 c. 29 s. 1654 (7) (c); 1977 c. 60, 293, 418; 1979 c. 102; 1981 c. 284; 1985 a. 29; 2009 a. 28, 244; 2011 a. 14. The failure to make a correction within the 30-day period under sub. (5) only estops an insurer from asserting one of the defenses listed in that subsection. Holmgren v. Strebig, 54 Wis. 2d 590, 196 N.W.2d 655 (1972). The 30-day notice requirement in subs. (4) and (5) is mandatory. Substantial compliance was inapplicable. Midwest Mutual Insurance Co. v. Nicolazzi, 138 Wis. 2d 192, 405 N.W.2d 732 (Ct. App. 1987). When the insured is also the operator, subs. (4) and (5) do not operate to estop an insurer from raising a "permission" defense. Nelson v. Zeimetz, 150 Wis. 2d 785, 442 N.W.2d 530 (Ct. App. 1989). Coverage of automobile liability insurance is not mandatory in Wisconsin, and a liability policy issued in Oregon with limits of $10,000 per person is not in conflict with this statute. Schanche v. Estate of Alvarez, 368 F. Supp. 543.