San Francisco, Apr 16 (IANS): Twitter, Inc. has announced that its Board of Directors has unanimously adopted a limited duration shareholder rights plan following an unsolicited, non-binding proposal to acquire Twitter by Tesla CEO Elon Musk.

The Rights Plan, often called the "poison pill", will reduce the likelihood that any entity, person or group gains control of Twitter through open market accumulation without paying all shareholders an appropriate control premium or without providing the board sufficient time to make informed judgments and take actions that are in the best interests of shareholders, according to the announcement made on Friday.

The Rights Plan does not prevent the board from engaging with parties or accepting an acquisition proposal if the board believes that it is in the best interests of Twitter and its shareholders, the company said.

The Rights Plan is similar to other plans adopted by publicly held companies in comparable circumstances. Under the Rights Plan, the rights will become exercisable if an entity, person or group acquires beneficial ownership of 15 per cent or more of Twitter's outstanding common stock in a transaction not approved by the board, it noted.

Musk announced on Thursday that he had made an offer to buy Twitter. The billionaire is willing to pay $54.20 per share to buy 100 per cent of the company. The all-cash offer will value the social network company at about $43 billion, Xinhua news agency reported.

He also acknowledged he was "not sure" if he would actually be able to buy Twitter, adding that there is a Plan B if his initial offer is rejected.