Matrix Receivables Limited v Musst Holdings Limited

In commercial litigation, identifying the party ordered to pay money is a highly relevant starting point for determining costs, but it is not decisive in every case. The court must evaluate success in substance and reality, considering the litigation as a whole and the parties’ conduct. Where a claimant obtains a modest recovery but fails on the principal claims, incurs disproportionate costs, and has pursued weak claims or acted unreasonably, the court may conclude that neither party was successful and make no order as to costs.

For an unjust enrichment claim based on receipt of money, enrichment accrues when the money is received. Each receipt may constitute a separate enrichment and cause of action. A future contractual entitlement or expectation does not itself constitute the benefit.

This was a consequential judgment following judgment for Matrix on part of its unjust enrichment claim concerning management fees received by Musst from introductions to customers. Matrix recovered £175,380.76 plus interest. Its larger unjust enrichment claim concerning performance fees, and its alternative contractual claims, failed.

The court considered interest, permission to appeal, costs and a stay of execution. Musst sought permission to appeal on the limitation issue, arguing that enrichment accrued when its agreement with Astra was made or when the first management fee was paid. The central costs issue was whether Matrix or Musst was the successful party, or whether the circumstances justified no order as to costs.

1. Interest. Interest under Senior Courts Act 1981, section 35 A, was discretionary. No interest was awarded for the period before assignment or proceedings because the unjust enrichment claim was not obvious, the delay was unjustified, and Musst was not at fault for failing to discover the claim. Interest was awarded for the period from commencement of proceedings to judgment at the US prime interest rate, without uplift.
2. Accrual and permission to appeal. The enrichment in an end-product case arose when Musst received money from Astra, not when services were provided, when Musst acquired an entitlement, or when a future payment was expected. Each receipt constituted a further enrichment. The limitation analysis therefore operated receipt by receipt. Musst’s proposed appeal had no real prospect of success and raised no other compelling reason for an appeal.
3. Costs. The “who pays the cheque” approach is highly relevant in commercial litigation, but it is not an inflexible rule or the whole analysis. Success must be assessed by reference to the litigation as a whole, applying common sense to the substance and reality of the result. The court may consider the value and importance of the issues, the relative success on principal and subsidiary claims, proportionality, conduct, and the availability and significance of settlement offers.
4. The payment to Matrix was important but not decisive. Matrix succeeded only on a small part of the management-fee claim, while its performance-fee claim and contractual claims failed. The performance-fee claim was the principal economic substance of the action, and the contractual claims had been maintained until trial despite being very weak. The conduct of Mr Reeves, including inconsistent evidence and assistance to Astra against Musst in related litigation, was also relevant under Civil Procedure Rules 1998, rules 44.2 and 44.4.
5. The court concluded that neither party was properly to be treated as successful. Alternatively, there were sufficient grounds to depart from any starting point that Matrix was the successful party. The appropriate order was no order as to costs. The parties agreed the terms of a stay of execution, which were accepted by the court.

This was a consequential judgment following the court’s earlier judgment in the same proceedings, [2025] EWHC 2487 (Ch). The earlier judgment awarded Matrix £175,380.76 plus interest on part of its unjust enrichment claim and dismissed the remaining claims. This judgment determined interest, permission to appeal, costs and stay of execution.