On 14 January 2022, the CAT issued a third judgment in the mass claim proceedings of Walter Hugh Merricks CBE against Mastercard. Merricks is the representative of a class seeking damages from Mastercard for violating competition laws in relation to the setting of multi-lateral interchange fees (“MIFs”), for which unlawful conduct Mastercard was fined by the European Commission (EC) in 2007. Since Merricks was granted a Collective Proceedings Order (CPO) for opt-out proceedings by the CAT’s 18 August 2021 decision, it was necessary for the order to specify the “domicile date”.
The “domicile date” has to be specified in the CPO for the purposes of determining whether a person is domiciled in the UK. A key element of opt-out claims is that claimants who fall within the class and who are domiciled within the UK are automatically included in the class unless they opt out. Because of the specific way the class was defined in the claim order in this case, the determination of the domicile date had even further implications.
Merricks sought a determination that the domicile date should be 6 September 2016, being the date the claim form was issued. Mastercard submitted that the domicile date should be 18 August 2021, when the decision to grant the CPO was made. If Merricks were to prevail, that would mean that all persons being alive on 6 September 2016 but who had died prior to the CPO date would be included in the class (by the personal/authorised representative of their estate). If Mastercard were to prevail, this entire group would be excluded.
Because of the size of the proposed class (potentially 46.2 million people) and the extended duration of almost five years between the issue of the claim form and the decision to grant a CPO, this issue was of particular importance in this case. The preservation of approximately 3 million claims was at stake.
The CAT sided with Merricks and ruled that the domicile date should be specified as the claim form date, i.e. 6 September 2016. However, the CAT also made clear that it reached this conclusion based on the specific circumstances of this case and that it considers it undesirable for future applications for the class definition to depend on the domicile date.
 MIFs are fees charged between banks for transactions using Mastercard-issued credit and debit cards.