Research and development (R&D) expenses for the fourth quarter of 2012 totaled $9.5 million, essentially flat from the $9.5 million recorded in the third quarter of 2012. Fourth quarter 2012 R&D expenses increased $0.5 million from fourth quarter 2011, mainly due to higher payroll and related expenses. Full year-over-year R&D expenses increased $2.8 million to $36.6 million primarily as a result of increased payroll and related expenses, including a $1.1 million increase in non-cash stock based compensation expense.
General and administrative (G&A) expenses for the fourth quarter of 2012 were $20.2 million, an increase of $2.8 million from the third quarter of 2012, primarily due to start-up activities related to the Columbus facility. Fourth quarter 2012 G&A expenses increased $14.3 million from fourth quarter 2011, also due to $11.5 million higher start-up related activities from to the Columbus facility and $2.4 million higher non-cash stock based compensation. Full year-over-year G&A expenses increased $36.2 million from 2011, mainly driven by $28.5 million higher Columbus related expenses, $5.9 million higher non-cash stock based compensation and higher other payroll related expenses.
Capital investments during the fourth quarter were $6.0 million, primarily related to KiOR's flagship 1,500 bone dry ton per day project in Natchez, KiOR's initial-scale commercial production facility in Columbus, and enhancements to KiOR's research and development facility.
KiOR had cash and cash equivalents of $40.9 million at December 31, 2012, which represents a $90.7 million decrease from the December 31, 2011 balance. This decrease was primarily driven by capital expenditures, operating uses of cash, and paying off previous business loans, partially offset by funding from the $75.0 million 4-year-term loan announced earlier this year. Net long-term debt stood at $126 million as of quarter-end. Subsequent to quarter end, the Company amended its 4-year-term loan to, among other things, extend KiOR's ability to pay interest in kind, defer principal amortizations, and increase the facility to $125 million to provide additional operating liquidity.