Gross profit totaled $1.61 billion, representing a year-over-year increase of 28.3%. Gross margin of 45.2% increased 640 basis points year-over-year, 20 basis points above the high-end of the Company’s guidance, principally driven by improved product mix, favorable pricing, and manufacturing efficiencies.
Operating income increased 34.8% to $885 million, compared to $657 million in the year-ago quarter. The Company’s operating margin increased 460 basis points on a year-over-year basis to 24.9% of net revenues, compared to 20.3% in the 2020 fourth quarter.
By product group, compared with the year-ago quarter:
Automotive and Discrete Group (ADG):
- Revenue increased in both Automotive and in Power Discrete.
- Operating profit increased by 129.5% to $216 million. Operating margin was 17.6% compared to 9.9%.
Analog, MEMS and Sensors Group (AMS):
- Revenue increased in both Analog and MEMS and decreased in Imaging.
- Operating profit decreased by 16.6% to $335 million. Operating margin was 26.6% compared to 28.3%.
Microcontrollers and Digital ICs Group (MDG):
- Revenue increased in both Microcontrollers and in RF Communications.
- Operating profit increased by 82.9% to $318 million. Operating margin was 29.9% compared to 20.3%.
Net income and diluted earnings per share increased to $750 million and $0.82, respectively, compared to $582 million and $0.63, respectively, in the year-ago quarter.
Cash Flow and Balance Sheet Highlights
| Trailing 12 Months | ||||||
| (US$ m) | Q4 2021 | Q3 2021 | Q4 2020 | Q4 2021 | Q4 2020 | TTM Change |
| Net cash from operating activities | 881 | 895 | 922 | 3,060 | 2,093 | 46.2% |
| Free cash flow (non-U.S. GAAP) | 314 | 420 | 512 | 1,120 | 627 | 78.6% |
Capital expenditure payments, net of proceeds from sales, were $548 million in the fourth quarter and $1.83 billion for the full year 2021. In the year-ago quarter, capital expenditures, net, were $381 million.
