Every single software team I've worked in or heard of in the USA? ;) Usually it's tied to the first meeting, I have a mind-destroying train wreck of a "scrum" 3 times a week at 11am so it doesn't make any sense to start before 11. When I used to wake up early consistently in a different team I tried to move the morning scrum to 7am, or maybe 8am, or maybe come on 9:30am?! But people weren't buying it. Meetings before 10am are only scheduled in extreme circumstance.