Your data as a consumer

Part of the transaction.

Rights over data

Regimes such as the GDPR let you ask what a company holds, get errors corrected, request deletion, and object to marketing.

Consent for marketing must be freely given and easy to withdraw.
Loyalty schemes trade discounts for detailed purchase histories.

After a breach

Companies must usually notify serious breaches, and you may be entitled to compensation for real harm. Watch for fraud attempts that follow, using the leaked details.