Sequentially, our EMS business’ gross margin declined 0.7 percentage points to 8.4% and while our operating margin declined 0.4 percentage points to 3.5%. The operating margin decline was driven primarily by product mix. Our EMS fourth quarter operating profit was NTD 2.8 billion, flat sequentially and down NTD 1.2 billion annually. From a full year perspective, our EMS business declined NTD 33.7 billion or 11%. Full year gross and operating profit declined by NTD 5.7 billion and NTD 5 billion, respectively. Full year gross and operating profit margins declined 0.9% and 1.3 percentage points, respectively. Generally, the full year declines in our EMS business are the result of the soft electronics market, leading to lower operating leverage.
On Page 12, you will find a graphical representation of our EMS revenue by application. The shifts here overall were generally due to product timing. Relative to previous years, some products were earlier, while others were later in accordance with customer requests. Further, our computing revenues were also higher, driven by stronger networking, server and general restocking revenues. On Page 13, you will find key line items from our balance sheet. At the end of the fourth quarter, we had cash, cash equivalents and current financial assets of NTD 72 billion. Our total interest-bearing debt was down NTD 27.5 billion to NTD 191.7 billion. Total unused credit lines amounted to NTD 373.8 billion. Our EBITDA for the quarter was NTD 28.6 billion, while our EBITDA for the year was NTD 106 billion.
Our net debt to equity this quarter was down to 0.38. On Page 11, you will find our equipment capital expenditures. Machinery and equipment capital expenditures for the fourth quarter in U.S. dollars totaled USD 234 million, of which USD 130 million were used in packaging operations, USD 76 million in testing operations, USD 21 million in EMS operations and USD 7 million in interconnect material operations and others. Machinery and equipment capital expenditures for the full year of 2023 in U.S. dollars totaled USD 914 million, of which USD 460 million were used in packaging operations, USD 314 million in testing operations, USD 114 million in EMS operations and USD 26 million in interconnect material operations and others. Current quarter EBITDA of USD 0.9 billion continues to outpace our equipment capital expenditures of USD 0.2 billion.
At this point, I would like to hand the presentation off to Dr. Tien Wu? Dr. Wu.
Tien Wu : Hi, everyone. This is Tien Wu. Year 2024 will be a year of recovery. In the last few years, there has been many changes. So, I think it’s appropriate for me to give you a market update, take a snapshot of what we see today and how ASE is competing in this new environment before I go to the year 2024 full year outlook. Let me talk about the semiconductor landscape. As you know, the semi organization and many analysts has been talking about NTD 1 trillion industry target by year 2030. We believe that the industry is likely to reach NTD 1 trillion revenue target in the next decade. It can be ’30, it can be ’31, ’32, ’33. But with high confidence, we think the revenue will be NTD 1 trillion mark in the next decade, driven by AI, robotics, EV and all of the new applications.
The industry has a clear understanding about our responsibility in net zero, ESG, circular economy as well as recycling throughout the whole supply chain. As a matter of fact, ASE has been putting a lot of endeavor in this area. Industry is facing challenges, geopolitical tensions, regionalization, market bifurcation. And with all of this new effect, it will be at a cost. Also, the reduced scale. Those are new variables that the industry need to learn how to manage. Industry will have a few things we need to do. First, industry has to propose more innovations with higher value. I think AI is a perfect example in that regard. Structural improvement of efficiency and cost. Everyone, the whole supply chain is putting a lot of effort in doing that.
Also, talent. We need to align talent workforce with the new complexities of doing business. With that, I would like to turn to the next page, how do we see ASE competing in this new environment. So, let me list a few competitive advantages and this is based on the feedback from all of our customers as well as internal via discussion. The first competitive advantage is technology. And here, I’m splitting the technology content into 4 large sector. Let me talk about the High Performance Computing or the AI arena. In that arena, I think the Taiwan ecosystem with foundry, with design companies as well as the whole supply chain becomes very critical. And ASE in this regard, we’re in the center of the Taiwan ecosystem. Also, specifically for AI and HPC, we do have the assembly and packaging and testing technology leadership.
On the SiP, no doubt, in the last 10 years, ASE has demonstrated clear leadership in heterogeneous integration as well as embedded devices. In the optical, we are slowly revealing our endeavor with all of our key customers in silicon photonics as well as co-packaged optics. We believe that will be the next paradigm shift, which will mark the new growth spur for the whole semiconductor industry, if that becomes a reality. And the last one is automation. ASE has been working on fully automated LiDAR factory, including software development, data collection as well as design ecosystem, including collaboration with designers as well as customers. So, we believe this 4 area will mark a strong competitive advantage for ASE in this new environment where the higher value of innovation becomes a key competitive requirement.
The next one will be scale efficiencies. From the financial performance in upcycle, also in the down cycle, we can pretty much see how do we compare to our peers in the industry on the financial performance as was cash flow. ASE will continue to abide for the strong financial discipline and we will make all the necessary investments according to our customers’ requirements as well as the technology trend in the industry. The next one will be flexibility and agility to handle business model evolutions. We believe that in the next 10 years, we have to work with different geography in a different business model. For example, we might choose, we might have to work with Tier 1 or OEM or system house directly in a different kind of business environment.
I think ASE in the last 20 years has demonstrated, we have a clear flexibility and agility to work with different companies in different geographies throughout the whole different business model and evolution. Lastly, will be the geographical diversity. I think ASE as well as ASE Holdco including USI, we do have the most diversified geographic presence throughout the world. With that advantages and also the resources, we should be able to handle all of the customer requirement in the next 10 years, depending on how the political environment varies. Please turn to the next page. I will talk about 2024 outlook. First, I want to talk about the revenue recovery. 2024 will be a year of recovery. We will be coming out of inventory adjustment in the first half.
We do expect growth to accelerate in the second half. Full year ATM revenue should grow at a similar rate with the logic semiconductor market. We expect a higher revenue mix of advanced packaging on technology leadership as well as testing revenue on the increase in turnkey ratio, just like what Ken has just shown you in the 2022 and 2023. We will target higher investment in machinery and building and smart factory compared to 2023. We believe we are entering into a new industrial upcycle and increasing adoption of advanced technology based on our customers’ feedback. Please turn to the next page. Let me talk about the advanced packaging and also the AI boom. In 2024, we’re on track to double our leading-edge advanced packaging revenue. From existing customers, we expect to have additional USD 250 million revenue in 2024, and we think the momentum will continue in the next few years.
ASE does have a comprehensive technology toolbox, including 3D, 2.5D, Fanout, SiP, co-packed optics, automation, et cetera. Our scale advantages and technology leadership will make ASE the preferred partner for our customers. As it is apparent today, we have mainly new NPI as well as collaborative project with many Tier 1 system customers, also the design house. ASE will not only benefit from the adoption of leading-edge advanced packaging but also the expansion of mainstream packaging, which will be utilized to address the growing semiconductor demand for all the surrounding chips of the booming AI. I’d like to turn the floor to our CFO, Joseph.
Joseph Tung: Okay. Thank you, Tien and hello, everybody. And to give you the guidance for first quarter of 2024. Based on our current business outlook and exchange rate assumptions, our guidance for the first quarter of 2024 to be as follows. In NT dollar terms, our ATM first quarter 2024 revenue and gross margin should be similar to the first quarter of 2023. Again, in NT dollar terms, our EMS first quarter 2024 revenues should be similar to the first quarter of 2023, and EMS first quarter 2024 operating margin should approach first quarter 2023 operating margin. Thank you.
