Hong Kong 50 Index is just a number that lets you track performance of the instruments comprising the index, so you can't invest in it directly. But you can buy Hong Kong 50 Index futures or funds or invest in its components.
The lowest ever quote of Hong Kong 50 Index is 14566.8 HKD. It was reached on Oct 31, 2022.
Hong Kong 50 Index reached its highest quote on Jan 29, 2018 — 33519.8 HKD.