Oman\'s Bank Muscat , the sultanate\'s largest bank by assets, will launch a rights issue in the second quarter of 2012, subject to regulatory approval, the bank said in a bourse statement on Thursday. The OR100m ($259.7m) rights issue will see shares offered at a 20-percent discount to market price, the statement said, although it added that further details about the offering would be published once it had got the regulator\'s sign-off. Standard & Poor\'s raised its long-term rating on Bank Muscat to A- from BBB+ last week, citing \"its strong business position, strong capital and earnings, moderate risk position, average funding, and adequate liquidity.\" At 0635GMT, the bank\'s shares were trading up 1.4 percent at 0.730 rials, although it was down 13.9 percent this year.