A couple months ago I asked Circle support how to get my instant limit increased and the agent told me Circle will only increase your limits when you ask for it and increased mine then. A few days ago, about a month after they increased my limit from $100 to $200 I requested it be upped to $500 instant access a week. They got back to me Memorial day morning and said my limit was increased to $1000! This could very well be old news to most of you but for the longest time I thought I had to wait for the increase so I just thought I'd pass the knowledge along.
Tl;dr: Circle only increases instant access limits when you ask and they're super cool about it.
Mine has been like that since day one. I thought it was the norm at first but I kept reading everyone having it at around $100-200. Good to hear it can be upped that easily.