1. The prohibition in Article 15 shall not apply to the activities referred to in Article 12(1)(a), provided that the person entering into a transaction, placing an order to trade or engaging in any other behaviour establishes that such transaction, order or behaviour have been carried out for legitimate reasons, and conform with an accepted market practice as established in accordance with this Article.

2. A competent authority may establish an accepted market practice, taking into account the following criteria:

(a) whether the market practice provides for a substantial level of transparency to the market;

(b) whether the market practice ensures a high degree of safeguards to the operation of market forces and the proper interplay of the forces of supply and demand;

(c) whether the market practice has a positive impact on market liquidity and efficiency;

(d) whether the market practice takes into account the trading mechanism of the relevant market and enables market participants to react properly and in a timely manner to the new market situation created by that practice;

(e) whether the market practice does not create risks for the integrity of, directly or indirectly, related markets, whether regulated or not, in the relevant financial instrument within the Union;