KARACHI (Reuters) - Pakistans foreign exchange reserves rose to $15.03 billion in the week ending on Jan. 2 from $13.96 billion the previous week, boosted by the arrival of an IMF loan tranche, a central bank official said on Thursday. Reserves held by the State Bank of Pakistan rose to $11.27 billion from $10.29 billion a week earlier, while those held by commercial banks also rose to $3.76 billion from $3.67 billion the previous week, the central bank spokesman said. The rise in central bank reserves incorporates $1.2 billion from the IMF (International Monetary Fund), said Syed Wasimuddin, chief spokesman at SBP. An IMF emergency loan package of $7.6 billion agreed in November 2008 helped avert a balance of payments crisis and shore up reserves. The IMF increased the loan to $11.3 billion in July and the central bank received a fourth tranche of $1.2b on Dec. 28. Foreign reserves hit a record high of $16.5b in October 2007 but fell steadily to $6.6b by Nov 2008, largely because of a soaring import bill.