The Hong Kong Monetary Authority has been kept busy on at least five occasions recently
- intervening to buy Hong Kong dollars against the USD
- to defend the HKD at the weak end of its trading band
(The HKMA have 7.85 for USD/HKD as their their limit)
All five instances of intervention have occurred between 5am and 6am HK time.
Which is 8am to 9am Sydney time (Hi HKMA, you're welcome ;-) )
A Bloomberg article describes the time of the day as "The Scariest Hour in FX":
- The early part of the Asian trading day -- when currency flash crashes tend to happen
