Under what circumstances is the liquidity provider not required to provide quote upon request?

The liquidity provider is not obliged to provide quote upon request in nine key situations:

(a) during a pre-opening session or a closing auction session (if applicable);

(b) during the first 5 minutes of each morning session or the first 5 minutes after trading commences for the first time on a trading day;

(c) when the warrant or CBBC or any underlying asset is suspended from trading for any reason;

(d) when there is no warrant or CBBC available for market making activities;

(e) if the theoretical value of the warrant or CBBC is less than HK$0.01;

(f) in the case of CBBCs only, upon the occurrence of a mandatory call event;

(g) where the underlying asset is an index, if there occurs or exists any suspension of, or limitation imposed on, trading of options or futures contracts relating to the index or if the index level is not calculated or published as scheduled for any reason;

(h) when there are operational and technical problems beyond the control of the liquidity provider that hinder the liquidity provider’s ability to provide liquidity; or

(i) if there is a “fast market” which materially affects the issuer’s hedging ability 

These circumstances are stated in the relevant listing documents and the relevant exemptions are set out in paragraph 3.3 of Industry Principles: http://www.hkex.com.hk/chi/prod/secprod/dwrc/Documents/principle_c.pdf