Following the strategic realignment and portfolio optimization discussed above, Standard Products Group revenue in the fourth quarter was $96.3 million, up 2.5% year-over-year on an "as reported" basis, and down 21.1% sequentially; and on an "as adjusted" basis, up 14.3% year-over-year.

The improved results in the Standard Products Group year-over-year were primarily attributable to a sharp increase in revenue from mobile OLED display driver ICs in connection with the introduction of new OLED smartphones from China manufacturers, which was offset in part by a strategic reduction of low-margin LCD business. In addition, the increase was also attributable to a higher demand for premium Power products such as high-end MOSFETs and IGBTs, primarily for TV and industrial applications.

Total Gross Profit and Gross Profit Margin
Total gross profit in the fourth quarter of 2018 was $43.9 million or 24.5% as a percentage of sales as compared with gross profit of $49.4 million or 28.3% in the fourth quarter of 2017, and $55.7 million or 27.1% in the third quarter of 2018.   

Segment Gross Profit Margin
Foundry Services Group gross profit margin was 23.2% in the fourth quarter of 2018 as compared with, on an "as reported" basis, 31.7% in the fourth quarter of 2017 and 24.4% in the third quarter of 2018. The Foundry Services Group gross profit margin was, on an "as adjusted" basis, 30.4% in the fourth quarter of 2017. The Standard Products Group gross profit margin was 25.6% in the fourth quarter of 2018 as compared with, on an "as reported" basis, 25.3% in the fourth quarter of 2017, and 28.8% in the third quarter of 2018. The Standard Products Group gross profit margin was, on an "as adjusted" basis, 25.9% in the fourth quarter of 2017.

Operating Income, Net Income, Adjusted Net Income, Adjusted EBITDA
Operating income, on a GAAP basis, for the fourth quarter was $7.9 million as compared with $7.6 million in the fourth quarter of 2017 and $18.3 million in the third quarter of 2018.

Net loss, on a GAAP basis, for the fourth quarter was $2.4 million or $0.07 cents per basic and diluted share as compared with net income of $43.7 million or $1.28 per basic share and $0.99 per diluted share in the fourth quarter of 2017, and net income of $17.2 million or $0.50 per basic share and $0.41 per diluted share in the third quarter of 2018.

Adjusted Net Income, a non-GAAP financial measure, for the fourth quarter of 2018 totaled $3.5 million or $0.10 per basic share and $0.10 per diluted share, as compared with Adjusted Net Income of $9.1 million or $0.27 per basic share and $0.23 per diluted share in the fourth quarter of 2017, and compared with Adjusted Net Income of $13.3 million or $0.38 per basic share and $0.32 per diluted share in the third quarter of 2018.

Adjusted EBITDA, a non-GAAP financial measure, in the fourth quarter was $17.4 million or 9.7% of revenue as compared with Adjusted EBITDA of $20.5 million or 11.8% of revenue in the fourth quarter of 2017, and compared with Adjusted EBITDA of $27.9 million or 13.5% of revenue in the third quarter of 2018.

Management believes that non-GAAP financial measures, when viewed in conjunction with GAAP results, can provide a meaningful understanding of the factors and trends affecting MagnaChip's business and operations and assist in evaluating our core operating performance. However, such non-GAAP financial measures have limitations and should not be considered as a substitute for net income or as a better indicator of our operating performance than measures that are presented in accordance with GAAP. A reconciliation of GAAP results to non-GAAP results is included in this press release.

Cash and cash equivalents totaled $132.4 million at the end of the fourth quarter, slightly down from $133.5 million at the end of the third quarter of 2018.  

Note: The following table sets forth information relating to our operating segments (in thousands).  The historical amounts below are presented both on an "as reported" and "as adjusted" basis to show the impact of the strategic realignment and transfer of a portion of the non-OLED Display business from the Standard Products Group to the Foundry Services Group beginning in the first quarter of 2018: