(3)In order to provide precise and comparable information, it is necessary to set out classes of financial instruments based on their characteristics relevant for publication purposes. A class of financial instruments should be narrow enough to reveal differences in order execution behaviour between classes but at the same time broad enough to ensure that the reporting obligation on investment firms is proportionate. Given the breadth of the equity class of financial instruments, it is appropriate to divide this class into subclasses based on liquidity. As liquidity is an essential factor governing execution behaviours and as execution venues are often competing to attract flows of the most frequently traded stocks, it is appropriate that equity instruments are classified according to their liquidity as determined under the tick size regime as set out in Directive 2014/65/EU.