Demutualisation rule: broker members barred from serving as exchange office bearers under SEBI directive to corporatise governance. SEBI amends the Articles of Association of the Calcutta Stock Exchange to remove the word 'elected' in the relevant article and to add a proviso that no broker member of the exchange shall be an office bearer, i.e. President, Vice President or Treasurer, thereby segregating ownership, management and trading membership to expedite corporatisation and harmonise governing board composition.