Cashback appears in an account as pending and stays there for weeks or months before becoming payable. The delay follows the money, which has to travel through several parties before anyone can safely release it.
The payment is a share of an affiliate commission
A cashback site is an affiliate. When a purchase is made through its link, the retailer pays it a commission and the site passes part of that to the shopper.
Nothing can be paid out until the commission itself is confirmed and settled, which the retailer does on its own schedule.
The site is therefore not holding your money. It is waiting for money it has not yet received.
Returns must be exhausted first
Commission is payable on a completed sale. If the item is returned, the retailer reverses the commission and the cashback disappears with it.
The pending period is generally set to outlast the retailer's return window, since paying early would mean recovering funds from shoppers afterwards.
Categories with long return periods or delayed fulfilment, such as travel and insurance, have correspondingly long pending times for exactly this reason.
Reconciliation runs in batches
Retailers, affiliate networks and cashback sites reconcile transactions periodically rather than continuously, often monthly.
A purchase can therefore wait for the retailer's cycle, then the network's, then the site's payment run, with each adding delay.
This is why cashback frequently arrives in a cluster on a particular date rather than trickling in as individual purchases settle.
Tracking failures are the common problem
Attribution depends on a tracking parameter surviving the journey from the cashback link to the completed order.
Ad blockers, browser privacy settings, opening another tab mid-purchase, or applying a code from a different site can break the chain, and the sale is then never associated with the click.
Claim processes exist for this, but they require order confirmation details and are usually subject to a deadline, so untracked purchases are worth checking within a few weeks.
Excluded purchases are defined narrowly
Most retailer terms exclude categories such as gift cards, certain brands, and orders where another discount code was applied.
Those exclusions are listed on the offer page and are the usual explanation for cashback that tracks correctly and is then declined.
Reading them before buying costs a minute and prevents structuring a purchase around a payment that was never available on that item.