How do charged black holes acquire their charge?

Black holes have three externally measurable properties, mass, angular momentum and charge. It’s clear how, when a massive star runs out of fuel and begins gravitational collapse, it retains the remaining mass and angular momentum of the parent star. But stars, being part of this Universe where symmetry seems to be a foundational rule, are essentially neutrally charged, in that they contain roughly the same number of positively, negatively, and neutrally charged particles. In such a symmetrical universe, how do charged black holes come into existence? From where do they acquire their charge?

This question continues the Black Hole Series. Previous entries included:
1  —  “Can a black hole overeat?”
2  —  “How big is your average black hole?”
3  —  “What happens when a black hole evaporates?”
4  —  “Would an ordinary black hole attract antimatter?”
5  —  “Could you kill an ordinary black hole by feeding it antimatter?”
6  —  “What is the morphology of a black hole?”

Also, @mattbrowne asked What exactly happens when a (hypothetical) antimatter black hole merges with a ‘normal’ black hole? shortly before I arrived here. That excellent question deserves to be part of the series. Feel free to add any other notable black hole questions from whatever date.