Bren Higgins
Executive Vice President & Chief Financial Officer at KLA
Thanks, Rick.
KLA's quarterly results demonstrated our market leadership combined with the consistent execution of our global team. KLA continues to serve resourcefulness and the ability to adapt to meet customers' changing requirements. Quarterly revenue was $2.57 billion, above the guidance midpoint of $2.5 billion. Non-GAAP diluted EPS was $6.60 and GAAP diluted EPS was $6.18, both above their respective guidance midpoints. Gross margin was 62.5% at the upper end of the guidance range as a richer product mix than model and higher revenue volume growth upside to guidance.
Operating expenses were $553 million. Operating expenses were comprised of $324 million in R&D and $229 million in SG&A. Operating margin was 41%. Other income and expense net was a $32 million expense and the quarterly effective tax rate was 12.6%. Quarterly non-GAAP net income was $893 million, GAAP net income was $836 million, cash flow from operations was $893 million, and free cash flow was $832 million. The company had 135.3 million diluted weighted average shares outstanding at the end of the quarter. The breakdown of revenue by reportable segments, end markets, major products and regions can be found within the shareholder letter and slides.
Turning to the balance sheet. KLA ended the quarter with $4.5 billion in total cash, cash equivalents and marketable securities. Debt of $6.7 billion and a flexible and attractive bond maturity profile supported by strong investment-grade ratings from all 3 major rating agencies. Moving to our outlook. We believe our business is transitioning from a period of stabilization to a resumption of growth, which began in our June quarter, and we expect to continue through the remainder of calendar '24 and into 2025.
For calendar 2024, we remain encouraged by the improvement in our customers' revenue and profitability over the course of this year. This improvement will ultimately translate into new investment in capital equipment to support semiconductor growth over the medium term. Our high-level outlook for the industry remains largely unchanged. Our expectation is for the WFE market to be in the mid-$90 million range and that the second half of the calendar year will be stronger than the first half.
While it's too early to be overly specific on expectations for calendar 2025, we do expect a year of growth through principally by growth in leading-edge investments in both logic/foundry and in memory. Given KLA's business momentum, we are confident in our relative performance opportunities moving forward. Daily September quarter guidance is as follows: Total revenue is expected to be $2.75 billion, plus or minus $150 million; foundry/logic revenue from semiconductor customers is forecasted to be approximately 80%; and memory is expected to be approximately 20% of semi process control systems revenue. Within memory, DRAM is expected to be about 83% of the segment mix and NAND the remaining 17%.
Gross margin is forecasted to be in the range of 61.5% plus or minus 1 percentage point, as higher revenue volumes offset by weaker anticipated product mix. Consistent with our comments last quarter, based on the current industry outlook, top line growth expectations for calendar '24, higher forecasted growth in services and expected system product mix, we are still modeling non-GAAP gross margins to remain relatively stable around the mid 61% range. Variability quarter-to-quarter is typically driven by product mix fluctuations.
Operating expenses are forecasted in the September quarter to be approximately $565 million as we continue to make important R&D and scaling investments to support expected revenue growth. Look ahead, we expect approximately $10 million to $15 million incremental growth in quarterly operating expenses for the remainder of calendar '24 and into 2025. This is supported by our revenue growth expectations and in line with our 40% to 50% incremental operating margin business model.
Other model assumptions for the September quarter include other income and expense net of approximately $34 million expense, GAAP diluted EPS is expected to be $6.69, plus or minus $0.60 and non-GAAP diluted EPS of $7 plus or minus $0.60. EPS guidance is based on a fully diluted share count of approximately 135 million shares.
In conclusion, our business has transitioned from a period of stabilization to one of growth. We remain optimistic that the indicators of improvement we have seen will continue throughout the remainder of calendar '24 and into 2025. KLA is focused on delivering a differentiated product portfolio that anticipates customers' technology road map requirements and drives our longer-term growth expectations.
With the KLA operating model guiding best-in-class execution, KLA continues to implement strategic objectives, which are geared to drive outperformance. KLA's focus on customer success, delivering innovative and differentiated solutions and operational excellence is what drives industry-leading financial and free cash flow performance and allows us to return capital consistently.
Return of scaling and increasing complexity has solidified our confidence in the increasing importance of process control in enabling technology advancements. This is not just an improving time to result in process integration and fab ramp, but also in optimizing yield across the volume production environment with high semiconductor device design mix. This bodes well for KLA's long-term growth outlook, as near-term industry demand trends are continuing to improve. In alignment with this, KLA's business is improving and the long-term secular trends driving semiconductor industry demand and investments in WFE remain compelling.
That concludes the prepared remarks. Let's begin the Q&A. Kevin?