The US dollar to the pound exchange rate will be adjusted to reflect the Brexit vote on March 5.
The move will mark the first time in almost five years that the UK will leave the European Union, a move that has triggered a sharp selloff in the pound.
The change comes as the pound is trading at a near four-year low against the US dollar.
A spokeswoman for the Office of the Director of National Intelligence, which oversees the National Security Agency (NSA), said the change will affect the exchange rate between the two currencies and the value of assets that trade between the US and UK.
She declined to say what the change would mean for the value that individuals and businesses use for buying and selling currency, but said the exchange rates could affect the timing and amount of money movements between the currencies.
“The change will have no effect on the timing of currency exchange rates, but it could affect how the US dollars are converted into the pounds sterling and pounds sterling to dollars,” the spokeswoman said in an email.
The Office of Intelligence and Analysis (OIA) said the changes were needed to protect the US government from potential future terrorist attacks in the US, which have increased dramatically since the Brexit referendum.
The OIA also said the move is necessary to avoid a significant reduction in the exchange-rate value of US assets that are used by the US financial services industry.
The US has also been hit by a major trade dispute with China, which is threatening to impose tariffs on imports of US goods from other countries.
The trade dispute between the world’s two biggest economies has triggered global trade talks between the leaders of the US Federal Trade Commission and the Chinese government, which are still underway.
“The OIA is committed to maintaining the credibility of the exchange system by providing a comprehensive, transparent, and efficient means for trading between the United States and the United Kingdom,” the agency said in a statement.