An increasingly used defense mechanism against hostile takeover is "Shark Repellants".

A hostile tender offer made directly to a target company's shareholders, with or without previous overtures to the management, has become an increasingly frequent means of initiating a corporate combination. As a result, there has been considerable interest in devising defense strategies by actual and potential targets. An increasingly used defense mechanism is anti-takeover amendments to the company's constitution or articles of association, popularly called shark repellants. The anti-takeover amendments have to be voted on and approved by the shareholders. Through this, the practice of the company to change the articles, regulations, bye-laws etc. tries to be less attractive to the corporate bidder. Anti-takeover amendments generally impose new conditions on the transfer of managerial control of the firm through a merger, tender offer, or by replacement of the Board of Directors. In India every company has the power to alter its articles of association by a special resolution. The altered articles will bind the members just in the same way as did the original articles. But that will not give the altered articles a retrospective effect. The alteration of articles of association is subject to the following restriction: The alteration must not be in contravention of the provisions of the Act, i.e. should not be an attempt to do something that the Act forbids. The power of alteration is subject to the conditions contained in the memorandum of association i.e. alter only the articles of the company as relate to the management of the company but not the very nature and constitution of the company. Also the alteration should not constitute a fraud on the minority.