- Underlying Q3 profit before tax rose 10 per cent- Net interest margins down four per cent over last nine months- October trading was in line with trends in latest nine months- Cost-efficiency ratio falls to 57 per centFTSE 100-listed global banking giant HSBC registered a 10 per cent rise in underlying profits before tax in the third quarter of 2013 to reach 5,056m dollars (3.14bn pounds). During the same period underlying revenue was broadly unchanged, at $15,588m (£9,682m), versus the $15,661m achieved in 2012. 'Clean' underlying revenue came in at $15,571m, ahead of the consensus estimate of $15,335m and Nomura's forecast of $15,145m. Meanwhile, the clean underlying profit before tax was $5,809m (consensus: $5,535m, Nomura: $5,509m).In regards to the most current trading conditions, HSBC said that they were "in line with the trends we experienced during the first nine months of the year". It also confirmed that it is one of a number of firms being investigated by the FCA and other regulators in relation with its dealings in the foreign exchange market. Net interest margin downNet interest margins decreased in the nine months to September 30th when compared with the same period in 2012 as a result of significantly lower gross yields on customer lending, including balances within 'Assets held for sale', the lender explained. HSBC added $400m of additional "sustainable cost savings" across all regions, taking the annualised total to $4.5bn since the start of 2011. That already exceeds the bank's target for the end of 2013.The cost-efficiency ratio, which compares overheads with income, fell back to 57%. Operating expenses higherUnderlying operating expenses in the latest quarter fell by 4% to $9,572m. However, excluding notable items, operating expenses increased reflecting higher investment expenditure, wage inflation and litigation and regulatory-related costs.The bank's core tier-1 ratio stood at 13.3% at the quarter-end, while its annualised return on equity (RoE) improved by 1.5 percentage points in the latest nine-month period to 10.4%, compared with 8.9% in the equivalent period in 2012.Reasons for optimism on outlook for global growth Regarding the outlook, management referenced "reasons for optimism" with some evidence of a broadening recovery. HSBC was positive on China, the US and the UK, although Latin America was expected to remain slow. Nevertheless, at one point in its statement HSBC added that "regulatory uncertainty remains".HSBC's forecasts for global growth remained constant at 2.0% in 2013 and 2.6% in 2014.As of Friday´s close shares of HSBC had underperformed the wider Stoxx 600 bank sector benchmark by 7%, although it had outperformed the same by 12% since July, analysts at Nomura wrote to clients before the release of the interim management statement, on Monday. "With recent underperformance and consensus not looking demanding, and with the bar lowered by recent peer results, we feel HSBC is well positioned in results on Monday", they added. A trading update call with analysts and shareholders is scheduled for 11:00. AB