Investment Firm (ABC) acts as executing broker on behalf of its Client (123) and gives up a trade for clearing to Investment Firm (XYZ) as clearing broker.
Under EMIR:
a. Firm ABC, acting as executing broker, does not have to report the transaction if the trade is given up to Firm XYZ within T+1 (and there has not been any change to the economic terms of the original trade);
b. Firm XYZ, acting as clearing broker, has to report the cleared transaction which includes the Client 123 identifier as counterparty to the contract and the Firm ABC identifier as executing broker; and
c. Client 123, as the originator of the order to trade and counterparty to the contract, has to report the cleared transaction which includes Firm XYZ identifier as counterparty to the contract and Firm ABC identifier as executing broker.
Firm ABC has to submit the order details only. This reporting must be done by delegation to the organised market place or third party service provider.
Firm ABC does not have to submit any trade report.
Source: REMIT Trade Reporting User Manual (TRUM)
See more general remarks on the EMIR/REMIT derivatives' reporting overlap.