1.   A CCP shall regularly review the models and parameters adopted to calculate its margin requirements, default fund contributions, collateral requirements and other risk control mechanisms. It shall subject the models to rigorous and frequent stress tests to assess their resilience in extreme but plausible market conditions and shall perform back tests to assess the reliability of the methodology adopted. The CCP shall obtain independent validation, shall inform its competent authority and ESMA of the results of the tests performed and shall obtain their validation before adopting any significant change to the models and parameters.

The adopted models and parameters, including any significant change thereto, shall be subject to an opinion of the college pursuant to Article 19.

ESMA shall ensure that information on the results of the stress tests is passed on to the ESAs to enable them to assess the exposure of financial undertakings to the default of CCPs.

2.   A CCP shall regularly test the key aspects of its default procedures and take all reasonable steps to ensure that all clearing members understand them and have appropriate arrangements in place to respond to a default event.

3.   A CCP shall publicly disclose key information on its risk-management model and assumptions adopted to perform the stress tests referred to in paragraph 1.

4.   In order to ensure consistent application of this Article, ESMA shall, after consulting EBA, other relevant competent authorities and the members of the ESCB, develop draft regulatory technical standards specifying:

(a)	the type of tests to be undertaken for different classes of financial instruments and portfolios;

(b)	the involvement of clearing members or other parties in the tests;

(c)	the frequency of the tests;

(d)	the time horizons of the tests;

(e)	the key information referred to in paragraph 3.

ESMA shall submit those draft regulatory technical standards to the Commission by 30 September 2012.

Power is delegated to the Commission to adopt the regulatory technical standards referred to in the first subparagraph in accordance with Articles 10 to 14 of Regulation (EU) No 1095/2010.