(1) For the purposes of this regulation "relevant funds" comprise the following -
(a) sums received from, or for the benefit of, a payment service user for the execution of a payment transaction; and
(b) sums received from a payment service provider for the execution of a payment transaction on behalf of a payment service user.
(2) Where -
(a) only a portion of the sums referred to in paragraph (1)(a) or (b) is to be used for the execution of a payment transaction (with the remainder being used for non-payment services); and
(b) the precise portion attributable to the execution of the payment transaction is variable or unknown in advance,
the relevant funds are such amount as may be reasonably estimated, on the basis of historical data and to the satisfaction of the FCA, to be representative of the portion attributable to the execution of the payment transaction.
(3) An authorised payment institution must safeguard relevant funds in accordance with either -
(a) paragraphs (5) to (11);
…