"It’s, um, standard in wizardry households -- at least in the "well-appointed’ ones -- that kids start out with a sort of trust fund post-Hogwarts. Parents set them up, I reckon? I don’t know, Marvolo -- Marvolo Slytherin -- mentioned he’d set it up because he sees Hermione as his responsibility. It’s money she can use while doing internships or an apprenticeship so she doesn’t immediately need paid work, like supporting her through uni, you see?"