(19)Trading in many non-equity financial instruments, and in particular derivatives, is episodic, variable and subject to regular modifications of trading patterns. Static determinations of financial instruments which do not have a liquid market and static determinations of the various thresholds for the purpose of calibrating pre-trade and post-trade transparency obligations without providing for the possibility to adapt the liquidity status and the thresholds in light of changes in trading patterns would therefore not be suitable. It is therefore appropriate to set out the methodology and parameters which are necessary to perform the liquidity assessment and the calculation of the thresholds for the application of pre-trade transparency waivers and deferral of post-trade transparency on a periodic basis.