SG&A expenses were $70.9 million for the March 2009 quarter, up $0.7 million, or 1% (a 13% increase on a constant currency basis) over the same period in fiscal 2008. SG&A expenses were favorably impacted by the appreciation of the US dollar against international currencies. This increase in SG&A was primarily due to expenses necessary to support sales growth. SG&A costs were 31% of revenue in the March 2009 quarter, compared to 33% in the same period in fiscal 2008.
R&D expenses were $13.9 million for the March 2009 quarter, or about 6% of revenue. R&D expenses decreased by 7% (a 22% increase on a constant currency basis) compared to the prior year quarter. R&D was also positively impacted by the appreciation of the US dollar against international currencies, particularly the Australian dollar. R&D outlays reflect ResMed’s continuing commitment to innovation within its product portfolio, as well as an ongoing commitment to clinical research and product development.
Amortization of acquired intangibles of $1.7 million ($1.1 million, net of tax) incurred during the quarter ended March 31, 2009, consisted of amortization of assets associated with our acquisitions of Resprecare, Hoefner, Saime and PolarMed. Stock-based compensation costs incurred during the quarter ended March 31, 2009 of $6.7 million ($4.9 million, net of tax) consisted of expenses associated with stock options granted to employees and our employee stock purchase plan.
For the nine months ended March 31, 2009, revenue was $668.8 million, up 11% over the nine months ended March 31, 2008. For the nine months ended March 31, 2009, income from operations and net income were $132.4 million and $101.1 million, up 25% and 25%, respectively, compared to the nine months ended March 31, 2008. Diluted earnings per share for the nine months ended March 31, 2009 were $1.31 per diluted share, up 28% compared to the nine months ended March 31, 2008.
Inventory, at $147.7 million, decreased by $10.6 million compared to June 30, 2008. Accounts receivable days sales outstanding, at 74 days, increased by 2 days compared to June 30, 2008.
Kieran T. Gallahue, president and chief executive officer, commented, In the third quarter of fiscal 2009, we continued to show strong growth year over year. Our favorable mix of product sales and market share gains led to a 23% increase in the Americas over the prior year quarter resulting in $122.5 million in revenue. As expected, sales outside the Americas were impacted by currency movements, in particular the depreciation of the Euro against the US dollar. As a result, sales outside the Americas decreased by 6% to $105.4 million, but were up 10% in constant currency terms. Cash flow from operations for the March 2009 quarter was a strong $44.2 million.
Our gross margin also expanded in Q3. This was a result of an increase in sales of our higher margin products, the depreciation of the Australian dollar and continued efforts to leverage cost efficiencies across our global organization. The market continues to respond well to our full range of products. The Easy Breathe motor technology has set a new standard in performance. Our new masks, including the Swift(TM) LT for Her and the Activa(TM) LT are well-positioned to improve patient comfort and compliance. Market efforts to improve compliance are also helping to drive sales of our feature-rich flow generators and our one-of-a-kind wireless Restraxx(TM) data system. We remain encouraged about the prospects for future market growth as the market for sleep disordered breathing therapy remains highly underpenetrated. As is widely known, there is a high prevalence of sleep-disordered breathing/obstructive sleep apnea in such co-morbidities as cardiac disease and diabetes, as well as in the transportation industry, and there is a vital public health need to diagnose and treat the disease in these groups. We remain committed to bringing innovative new products to market, and plan an active introductory schedule over the next 12-18 months.
