Section 6616. Extraordinary assessments; assessment corporations

(a) The
  members of every assessment corporation shall be contingently liable for
  extraordinary assessments sufficient to remove  any  impairment  in  the
  reserves required by this article.
    (b) Any assessment corporation if issuing policies on but one class of
  property,  may  levy an extraordinary assessment upon all its members in
  proportion to the several amounts of insurance held by each.
    (c) Any assessment corporation if issuing policies on  more  than  one
  class  of  property,  may  levy  an extraordinary assessment at rates of
  assessment determined in proportion to the amounts of insurance held  by
  each  on  the basis of classifications adopted by its board of directors
  to express the relative hazards of the properties insured.
    (d) Any assessment corporation if collecting assessments in advance on
  the initial and anniversary dates of policies may levy an  extraordinary
  assessment  determined  by  applying  to  the  assessment  earned on the
  members' policy or  policies  in  force  during  the  fiscal  year  next
  preceding  the  levy  of  additional  assessment, the ratio of the total
  additional assessment to the total assessment earned during said  period
  on all policies.
    (e)  No  extraordinary assessment shall be made by any such assessment
  corporation until after approval by the superintendent and if made shall
  be in each case, an amount equal to the members' proportionate share  of
  such impairment as specified herein.
    (f)  Any  assessment  corporation  which  levies annual assessments in
  advance may if its by-laws provide, limit the contingent liability of  a
  member  thereof  to  not less than once the amount of and in addition to
  the annual assessment which would be charged for insurance for one year.