Net sales in Q4/2013 were NT$4,315 million, an increase of 5.3% quarter-over-quarter from NT$4,097 million in Q3/2013, and an increase of 74.8% year-over-year from NT$2,468 million in Q4/2012. The sequential increase in revenue was driven mainly by lower OEM business as a percentage of shipment, while ASP improved moderately offset by slightly lower shipment. On a full year basis, net sales in 2013 were NT$15,098 million, an increase of 8.1% year-over-year from NT$13,966 million in 2012. We shipped 1.38GW of solar products, representing an increase of 24% year-over-year.
Gross profit in Q4/2013 was NT$537 million, compared to gross loss of NT$153 million in Q3/2013 and gross loss of NT$663 million in Q4/2012. Gross loss in Q3/2013 included one-time long-term contract related charges of NT$694 million. Gross margin was 12.5% in Q4/2013, compared to 13.2% in Q3/2013 on an adjusted basis and -26.9% in Q4/2012. Our underlying gross margin declined moderately due to wafer cost increases, partially offset by higher conversion efficiency. Full year 2013 gross profit was NT$434 million and gross margin was 2.9%, or NT$1,107mn and 7.3% on an adjusted basis.
Net profit in Q4/2013 was NT$243 million, compared to net loss of NT$453 million or net profit of NT$241 million on an adjusted basis in Q3/2013, and net loss of NT$1,195 million in Q4/2012. Net margin was 5.6% and earnings per share came in at NT$0.61 in Q4/2013, compared to net margin of 5.9% and earnings per share of NT$0.67 in Q3/2013 on an adjusted basis. Full year 2013 net loss was NT$591 million, compared to net loss of NT$1,924 million in 2012. Net margin was -3.9% and loss per share came in at (NT$1.65) in 2013, compared to net margin of -13.8% and loss per share of (NT$5.68) in 2012.
We are pleased to report that, excluding the aforementioned one-time items in Q3/2013, we turned profitable in full year 2013 and posted net income of NT$82 million or earnings per share of NT$0.23. This return to profitability is driven by strong shipment growth, improving pricing environment, R&D efforts and continuous cost reduction. With the evolution of global PV markets and the confidence in demand growth, we expect to expand our capacity to 1.8GW by yearend from 1.5GW currently. We also look forward to delivering more values by seeking vertical integration opportunities.
