The maximum holding speeds will vary depending on where in the world you will be holding. In fact, the holding speeds will vary depending on whether the holding procedure uses PANS-OPS First Edition or Second Edition Criteria.

This table summarizes the difference between US published maximum holding speeds and ICAO Standard speeds. Confused? A prudent and conservative suggestion would be to adopt the ICAO Standard  PANS-OPS Second Edition speeds and if not operationally  there are not feasible request a deviation from ATC. If you would like to see specifically what the country specific maximum speed is, you would locate that information in ICAO Doc. 7030, or in the Jeppesen text pages for terminal procedures.