Vedanta sweetened the deal for Cairn India Ltd. shareholders by increasing the number of preference shares four times to salvage a deal which would help create a natural-resources group to compete with BHP Billiton and Vale. Vedanta will offer minority shareholders of Cairn India one equity share and four redeemable-preference shares with a face value of 10 rupees each, it said in a statement Friday. The preference shares will carry a coupon of 7.5% and tenure of 18 months. The revised deal implies a 20% premium to the one-month volume weighted-average price of Cairn shares, according to the statement.