Foreign exchange reserves rose by $23.7 million to $12,544.5 million in the week ending on October 21, the State Bank of Pakistan (SBP) said on Saturday. Reserves held by SBP rose to $10,315.4 million from $10,255.0 million a week earlier, while those held by commercial banks fell to $2,229.1 million from $2,265.8 million.