15. Trade debtors, accrued income and deferred costs

Accounting policies

Customers and debtor balances are amounts to be received regarding goods sold or services rendered in the ordinary course of the business. They are initially recognised at fair value, being subsequently measured at amortised cost in accordance with the effective interest rate method, net of any impairment losses (notes 2.4.1. and 2.5.).

Non-current debtors include €51 million (€50 million in 2022) relating to additional tax liquidation as well as pre-paid tax. The Group has already contested the amounts paid and made a legal claim for reimbursement (note 24).

The increase in other current debtors is mainly explained by advances for the acquisition of tangible fixed assets.

As of 31 December 2023, the Group had a treasury investment in the amount of €135 million, with maturities between February and May 2024, which do not qualify as a cash equivalent.

Accrued income includes basically supplementary gains contracted with suppliers, in the amount of €397 million (2022: €323 million).

The deferred costs include €5 million of rents pay in advance, €1 million of loans issued expenses, €5 million of insurance costs and €13 million of other costs attributable to future years and paid in 2023, or, if not yet paid, already charged by the entities.

Current debtors with overdue amounts are subject to an analysis of the probability of future losses, based on historical information, taking into account the nature of the commercial relationship established, as well as to existing collateral and credit insurance, with reinforcements/reversals of adjustments for impairment losses recognised when justified (see note 29.2.1.).

The ageing analysis of debtors that are past their due date is as follows:

Of the debtors balances not considered impaired, €2 million (2022: €0.4 million) are covered by credit guarantees and credit insurance.

Movements on impairment of trade receivables are as follows: