Sentence:  Christiana Securities Company and Delaware Realty + Investment Company , major stockholders in du Pont , and the stockholders of Delaware were dealt with specially by provisions <WSD>requiring</WSD> the annual sale by a trustee , again over a ten year period , of du Pont 's General Motors stock allocable to them , as well as any General Motors stock which Christiana and Delaware owned outright . 
Meaning of the word marked with <WSD> tags:  require as useful, just, or proper