What happened: Hamburg want Fábio Vieira back after his productive loan but are prepared to pay only about €10 million, roughly half the purchase option. Arsenal are holding out for €20 million plus add-ons as talks stall.

Why it matters: The gap leaves Vieira's future unresolved before preseason and gives Arsenal little incentive to sell early. Hamburg could revisit negotiations later in the window if Arsenal receive no stronger offer.

What to watch: Watch whether another buyer meets Arsenal's valuation or Hamburg raises its offer before the window closes.