HMDS Period & Bar Size | Interactive Brokers

Valid Period Units:

Unit	Description
S	Seconds
d	Day
w	Week
m	Month
y	Year

Note: These units are case sensitive.

Valid Bar Units:

Duration	Bar units allowed	Bar size Interval (Min/Max)
60 S	secs	mins
3600 S (1hour)	secs	mins
14400 S (4hours)	sec	mins
28800 S (8hours)	sec	mins
1 d	mins	hrs
1 w	mins	hrs
1 m	mins	d
1 y	d	w

Note: These units are case sensitive.

NOTE: Keep in mind that a step size is defined as the ratio between the historical data request’s duration period and its granularity (i.e. bar size). Historical Data requests need to be assembled in such a way that only a few thousand bars are returned at a time.