India, May 14 -- bluebird bio, Inc. (BLUE), a biotechnology company, Carlyle (CG) and SK Capital Partners, LP Wednesday said they have amended their agreement pursuant to which Carlyle and SK Capital will purchase all outstanding shares of bluebird. bluebird bio shares were more than 50% up in pre-market.

As per the amended agreement, bluebird stockholders can elect to receive either the original offer of $3 per share in cash plus a contingent value right (CVR) of $6.84 per share in cash payable upon achieving a sales target, or $5 per share in cash.

The companies noted that stockholders who have previously tendered their shares and now choose to receive $5 per share must withdraw and re-tender their shares.

The amended tender offer expi...