KARACHI (Reuters) - Pakistans foreign exchange reserves fell to $16.91 billion in the week ending Nov 12, down from $16.95 billion the previous week, the State Bank said on Monday. Reserves held by the State Bank of Pakistan (SBP) fell to $13.13 billion from $13.18 billion in the week ending Nov. 5, while those held by commercial banks rose to $3.78 billion from $3.77 billion, the SBP said in a statement. Pakistans reserves hit a record high of $17.10 billion in the week ending Oct. 15 because of an increase in remittances from overseas Pakistanis and a narrowing trade deficit. They were further boosted in September after the IMF sent Pakistan $450 million and said that the money would go toward the budget to help with additional spending for flood relief and immediate foreign exchange needs. This was separate from the $11 billion IMF bailout programme, agreed in 2008. In May, Pakistan received $1.13 billion, the fifth tranche of the programme. The IMF is due to present Pakistans case to its board in December for the possible approval of the sixth tranche.