The currency peg for the HKD keeps USD/HKD in the range of 7.75 to 7.85. Higher is a weaker HKD.
The HKMA is obliged to intervene when the Hong Kong dollar hits 7.75 or 7.85 to keep the band intact.
During my years at ForexLive I have never failed to dismiss suggestions the HKD would weaken past 7.85. The currency band has been intact since 2005, with other pegged rates prior to that.
Dunno. Comments welcome.
HKD back to 2008. I could dig up a longer teerm chart, but you get the ocitrure of how the band has held quite well from this: