Pablo Brizzio
Analyst · the Securities and Exchange Commission and on Page 2 in today's webcast presentation.
With that, I'll turn the call over to Mr. Brizzio
Thank you, Sebastian. Good morning, and thank you very much for participating in this conference call. We will first give a quick look of our results for the quarter and then we will go to the Q&A section.
First of all, let me say that we are very happy to say that Ternium continues to show an excellent performance quarter-after-quarter, focusing in regional markets and providing high value-added product and services following the strategy of differentiation and cost reduction. Our efforts have been showing that we consistently report higher margins than our peers in the region. Also, we are positive about the future of our main market. We remain confident in the future performance of the Mexican market, and we are seeing a gradual recovery of Argentine's economy. Regarding the agreement to acquire CSA, we continue on working in the necessary steps for the closing of the transaction and expect we should close as anticipated by the third quarter of the year.
With that, let's begin on Page 3 of the webcast presentation. EBITDA in the first quarter 2017 was for $465 million, 33% higher than in the fourth quarter of 2016. The chart on the upper right side of the slide shows that EBITDA margin was 23% in the first quarter. This is equivalent to an EBITDA per ton of $188. The reason for the sequential increase in EBITDA per ton was a $46 increase in revenue per ton as operating costs per ton remained relatively stable.
We expect to maintain in the second quarter of the year the strong EBITDA level of the first quarter with higher shipments and slightly lower EBITDA per ton. In the first quarter of the year, we have net income of $310 million, equivalent to earnings per ADS of $1.33, a $0.73 sequential increase. Part of this increase were related to a very low effective tax rate in the quarter of only 10%, mainly as a result of the noncash gain on deferred tax of the 10% appreciation of the Mexican peso during the first quarter which increased, in U.S. dollar terms, the tax rate used to calculate deferred tax in our Mexican subsidiaries which have the U.S. dollar as their functional currency.
In the following page, we can see that in the first quarter, net sales increased 15% in Mexico, with 9% higher shipments and 6% higher revenue per ton. Steel prices in Mexico increased during the first quarter of the year, and realized price in the quarter also added to the increase in prices in connection with the regular price reset of quarterly contracts.
We expect sequentially higher shipment volumes in Mexico in the second quarter, reflecting healthy industrial consumer demand, especially in the automotive and household appliances industries, as well as a restocking in the construction-related value chain. We also expect an increase in realized price in this market during the second quarter, mainly related to the price reset of contracts.
Let's review now the southern region market performance on Page 5. In this market, net sales increased 3% as a result of 9% higher revenue per ton, partially offset by 6% seasonally lower shipments. We're anticipating a sequential and year-over-year increase in shipments in this region as steel demand is gradually growing, mainly supported by the agroindustry and public infrastructure investments in Argentina.
On the next page, we see a combined effect of these developments in our consolidated sales, a 10% increase in net sales with 6% higher revenue per ton and 4% higher shipments.
Let's go to the drivers of the sequential increase of this EBITDA in Page 7. Price was the main contributor here helped by higher shipments with more offset of slightly higher cost. As anticipated, higher prices of slabs did not flow through cost of sales yet in the first quarter of the year. This is something we should see having a stronger effect from the second quarter on. And the same is true for coal cost in Argentina, our -- excuse me, in Siderar, our Argentina subsidiary.
In the following page, Page 8, we can see that the majority of the differences between net income in the first and the second quarter was a substantial increase in operating income; lower income tax, as I mentioned at the beginning of the call; and better results from nonconsolidated companies, partly offset by higher net financial expenses.
On Page 9, we can see the free cash flow. We had a significant increase in working capital that absorbed a substantially part of the EBITDA generated in the quarter, leading to almost no free cash flow generation. The increase in working capital was, in great part, reflecting the increasing cost of slabs and other raw materials, like coal, in our inventories as well as somewhat higher inventories volume of steel and raw materials due to an increased level of shipments in the first and second quarter of this year. These represented $233 million of the $318 million increase in working capital. In addition to that, the net impact of trade and other receivables and payables was the use of cash of $84 million (sic) [ $85 million ] mainly reflected higher volume and prices of steel sales.
Going now to Page 10, you can see an evolution of Ternium's quarterly cash flow from operations, Capex and free cash flow. On the upper right corner, CapEx remains relatively stable, maybe a bit lower than normal. The company net debt remains stable at $0.9 billion, and the net debt to last 12 months' EBITDA ratio continued decreasing, with a 0.5x at the end of March 2017.
Okay. These were the main points I wanted to touch today. So please, operator, let's go now to the Q&A session. Thanks.