Kuwait's Boubyan Bank has received regulatory approval to issue a capital-boosting sukuk worth $250 million, the bank said in a bourse filing on Wednesday. The lender received approval from the Kuwaiti central bank to issue Basel III compliant Islamic bond that will enhance its Tier 1, or core, capital, it said. The bank will take a final decision on the sukuk and its timing after receiving all other approvals, the bank added.