Good evening. I am Hideki Somemiya, CFO of Resonac Holdings Corporation. I would like to express my sincere gratitude for your continued understanding and support of our company. Today, I will present an overview of the financial results for the first half of the fiscal year ending December 2025. Please refer to the second slide, "Key Takeaways." There are two main points I would like to share with you today. The first is the improvement in core operating profit compared to the same period of last year. This was due to the semiconductor and the electronic materials segment performing well this year, offsetting the underperformance of the chemicals segment. The second is the steady progress made against the forecast for FY 2025, announced on February 13th. Consequently, the annual guidance is kept unchanged at this time.
We will now proceed to the explanation of the results for the first half of FY 2025. Please turn to page three. This slide shows the consolidated results for the first half compared to the same period last year. First, revenue for the six months was JPY 642.1 billion, while the semiconductor and electronic materials segment saw a significant increase in revenue compared to last year. The mobility segment and the chemicals segment saw declines in revenue, resulting in a decrease of JPY 27.5 billion. Core OP was JPY 34.6 billion, an increase of JPY 1.4 billion from last year. Non-recurring items, one line below, caused a significant decrease in profit year-on-year, mainly due to business restructuring costs and the absence of the gain on sale of former head office building and land recorded last year.
OP was JPY 2 billion less than the core OP at JPY 32.6 billion, down JPY 17.1 billion year-on-year due to the absence of the gain on the sale of the former head office. Profit attributable to owners of the parent was JPY 19.7 billion, reflecting the absence of the sale of the former head office as well as the impact of foreign exchange losses rather than gains, resulting in a decrease of JPY 25.6 billion compared to the same period last year. EBITDA was JPY 82.1 billion, nearly unchanged from last year. With EBITDA margin at 12.8%, an improvement of 0.5% year-on-year, EBITDA margin, excluding Crassus Chemical, which is currently in the process of partial spinoff discussion, was 16.3%. Page four, please. The graph shows the factors behind the difference between core operating profit of JPY 34.6 billion this year and JPY 33.2 billion last year.
Looking at the breakdown of the JPY 1.4 billion increase from the same period of last year, sales volume contributed JPY 5.7 billion, with the improvement in the semiconductor and electronic materials segment accounting for the majority of this. Next, sales price was positive JPY 2.1 billion. Although there was a negative impact from the slight yen appreciation, this was offset by price increases implemented to pass on costs. Fixed and variable costs were a negative factor of JPY 6.2 billion, primarily due to the increases in fixed costs, such as labor costs and rising raw material costs, resulting in a decrease in profit in all segments. Finally, others were a negative factor of JPY 0.2 billion. The main factor was the impact of inventory valuation difference, with improvements and deteriorations varying by segment. For example, the semiconductor and electronic materials segment.
Profit improved in the hard disk media business due to the clearance of high-cost inventory, while in Crassus Chemical, profit deteriorated due to the significant decline in naphtha prices in the January-June period. Page five and six show variance analysis of OP by segment. Please refer to them later. Let us move to slide seven, which shows results by segment. You can see year-on-year changes in revenue, core OP, and EBITDA margin by segment. The semiconductor and electronic materials segment achieved revenue and profit growth, driving overall performance for the six-month period. On the other hand, other segments saw decreases in revenue and profit, with the chemicals segment experiencing a significant decline due to the downturn in the graphite electrode market. Segment summaries are available on slides 8- 12. First, on slide eight, semiconductor and electronic materials saw a 10% increase in revenue to JPY 230.7 billion.
Core OP increased by JPY 15.9 billion- JPY 42.5 billion. The increase in revenue and profit was primarily driven by semiconductor back-end materials, which saw increased sales volumes for advanced semiconductors, such as those for AI applications, and device solutions, which benefited from the recovery in data center demand, including increased sales of hard disk media. The segment's EBITDA margin improved from 22.5%- 27.8%, reaching 28.3% for the most recent quarter. Next, page nine shows mobility. Revenue increased by 10% year-on-year to JPY 89.7 billion. Core operating profit decreased by JPY 1 billion- JPY 1.3 billion. The majority of the decrease in revenue was due to the transfer of businesses, such as secondary battery packaging materials and food packaging materials, during the March quarter. Additionally, the downturn in the automotive market in Thailand also contributed to the decrease in revenue and operating profit. Page 10 shows innovation-enabling materials.
Revenue decreased slightly year-on-year to JPY 44.9 billion, and core operating profit decreased by JPY 0.7 billion- JPY 4.9 billion. The primary factor was the downturn in the automotive market. Page 11 shows chemicals. Revenue decreased 20% year-on-year to JPY 78.4 billion. Core operating profit decreased by JPY 7.9 billion to a loss of JPY 8.2 billion. The majority of the decrease in revenue and profit was attributable to the graphite business, which saw deterioration in both sales volume and pricing due to the sluggish graphite electrode market. Additionally, the absence of the reversal of the inventory write-down recorded last year under the lower-of-cost or market method also contributed to the decrease. Finally, page 12, Crassus Chemical. Revenue decreased 4% year-on-year to JPY 149.9 billion. Core operating profit is down JPY 2.9 billion to a loss of JPY 0.8 billion.
The decline in naphtha prices led to lower selling prices and revenue, and the deterioration in inventory valuation difference also contributed to the decrease in core operating profit. That was my explanation on the segment results. Page 13 shows non-recurring items on the left and the financial income and cost and equity in earnings of affiliates on the right, with year-on-year changes. Non-recurring items on the left show deterioration of JPY 18.5 billion. This was due to the recognition of the gain on sale of former head office land and buildings in the same period last year. For the six-month period ended in June, there were no significant changes in those items from the March quarter.
We had gain on business reorganization and others of JPY 6.6 billion, including the transfer of the secondary battery packaging materials and the food packaging materials business, as well as business restructuring expenses and extra retirement payments, together amounting to a negative JPY 5.5 billion, mainly from the graphite electrode business. Let me make a clarification here. Non-recurring items shown here were recognized for the January-June period. On August 1st, we announced the loss of approximately JPY 25 billion to be recognized in the third quarter or later due to the transfer of FEM Energy Technology, which primarily operates the lead-acid battery business. Please note that this business transfer is already included in the forecast for this fiscal year's guidance announced in February. Next, financial income and costs on the right-hand side deteriorated by approximately JPY 9 billion year-on-year.
The main factor was foreign exchange losses caused by the yen's appreciation compared with the gains recorded in the previous year. Finally, equity in earnings of affiliates improved JPY 1.9 billion compared to the same period last year, partly due to the impact of one-time cost adjustments recorded last year. Slide 14, consolidated statement of financial position. On the left-hand side, total assets were JPY 2,035.5 billion, a decrease of JPY 137.1 billion from the end of the fiscal year. The decrease was primarily due to the decline in cash and cash equivalents from bond redemption, as well as the decrease in assets held for sale, included in other current assets on this table due to the sale of regenerative medicine business. Total liabilities were JPY 1,361.8 billion, a decrease of JPY 118.9 billion from the end of the previous fiscal year.
This was due to a decrease in interest-bearing debt, as well as a decrease in liabilities directly associated with the assets held for sale following the completion of business transfers. Total equity decreased by JPY 18.2 billion from the previous fiscal year end to JPY 673.8 billion. The primary factor was appreciation of the yen against the dollar to JPY 144.8 as of the end of June, as shown in the appendix, which reduced FX translation adjustment or exchange differences on translation foreign operations under IFRS by JPY 24.3 billion. Let me comment on the major indicators shown at the bottom of the slide. First, the net debt-to-equity ratio increased from 0.74x to 0.97x , primarily due to the early repayment at the end of April of JPY 137.5 billion of subordinated loans recognized as 50% equity by Japan Credit Rating Agency through regular bank loans.
We will continue to target a net debt-to-equity ratio of 1.0 or below on a stable basis and strive to improve our financial structure. Finally, the ratio of equity attributable to owners of the parent to total assets, which was previously called the equity ratio, remained nearly unchanged at 31.8%. Page 15 onwards are appendices. Please refer to them as appropriate. That concludes my explanation. Thank you very much.