UPDATE 3-Deutsche, Commerzbank CEOs warn of ECB rate cut side effects <!-- no image --> <div>* Commerzbank CEO says ultra-low rates not sustainable (Updates with BlackRock CEO, additional Sewing quote)<div class="feedflare"> <a href="http://feeds.reuters.com/~ff/reuters/UKBankingFinancial?a=7mEBnXKaCj4:xq5jy1IroXs:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/reuters/UKBankingFinancial?d=yIl2AUoC8zA" border="0"></a> <a href="http://feeds.reuters.com/~ff/reuters/UKBankingFinancial?a=7mEBnXKaCj4:xq5jy1IroXs:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/reuters/UKBankingFinancial?i=7mEBnXKaCj4:xq5jy1IroXs:V_sGLiPBpWU" border="0"></a> <a href="http://feeds.reuters.com/~ff/reuters/UKBankingFinancial?a=7mEBnXKaCj4:xq5jy1IroXs:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/reuters/UKBankingFinancial?i=7mEBnXKaCj4:xq5jy1IroXs:F7zBnMyn0Lo" border="0"></a> </div><img src="http://feeds.feedburner.com/~r/reuters/UKBankingFinancial/~4/7mEBnXKaCj4" height="1" width="1" alt=""></div> Posted by Reuters