Del. Code tit. 5, § 1913

When, from the distribution of the profits of any building and loan association, the profits accruing to any series of stock show that the series has matured according to the provisions of the bylaws of the association, the association shall not make any further investment of its funds until all of the matured series of stock has been paid the owners thereof. The building and loan association shall allow the owners of matured stock interest at the rate of not less than 5 percent per annum upon the matured value of the series of stock during the time after the first month that the same remains unpaid. In no case shall the retirement of the stock be deferred longer than for a period of 12 months after the stock has matured.