John Guthrie
Analyst · RBC Capital Markets
Thanks, Doug. Before I begin, I wanted to highlight a new table in the press release and 10-K that reconciles net sales, organic sales and a new metric, organic daily sales, which we define as organic sales divided by the number of selling days in the relevant reporting period. We find that metric useful and plan on using it to help explain sales trends going forward.
Now turning to Slide 7 for our fourth quarter and full year 2016 results. We reported a net sales increase of 6% to $362 million in the fourth quarter compared to $340 million in the fourth quarter of the prior fiscal year. Net sales for the fiscal year 2016 increased by 14% to $1.65 billion compared to $1.45 billion for fiscal 2015. We had 61 selling days in the fourth quarter of 2016 compared to 65 selling days in the fourth quarter of 2015. Organic sales declined by 3% for the quarter, but organic daily sales increased 3%. For the year, organic sales increased 3% and organic daily sales, reflecting 3 less selling days, increased 4%.
In both the fourth quarter and for the year, we saw strength in our irrigation, hardscapes, nursery, lighting and landscape accessory products, reflecting continued strong growth in both the new construction and repair and remodel end markets. Organic daily sales for these products grew 8% for the quarter and 7% for the year. Nursery sales, which we called out last quarter as being weaker than the other product lines, saw a nice recovery, experiencing 7% organic daily sales growth for the quarter and 5% for the year. Organic daily sales for agronomic products, like fertilizer and control products, declined by 3% for the quarter and were flat for the year. Over the course of both the quarter and the year, organic growth for these products was negatively impacted by modest price inflation, weakness in the sales of ice melt products and branch closures and consolidations.
With respect to that last point, as part of our ongoing process to optimize our branch footprint, we closed and/or consolidated approximately 19 of our smaller primarily agronomic branches during the end of 2015 and through the first half of 2016. We estimate that these actions had a negative impact of approximately 2 percentage points on the annual organic growth for our agronomic products. Most of these branch closings or consolidations are the combination of 2 small branches in the market or the consolidation of a smaller branch into a larger branch. For example, in upstate New York, we combined a branch in Albany with a similar branch in Clifton Park.
Acquisitions play a role in this, and our acquisition of Shemin in 2015 provided several of these opportunities. Overall, these actions increased our EBITDA, but they tend to negatively impact organic sales. Pricing across all product lines was flat for the quarter and contributed approximately 100 basis points for the year. Acquisitions in the fourth quarter contributed approximately $30 million of sales growth or an additional 9% to our growth rate. For the full year, acquisitions contributed $157 million of sales growth or 11% to our overall growth rate.
Gross profit increased 7% to $112 million in the fourth quarter compared to $105 million in the fourth quarter of the prior year. Gross margin was 30.9% for the quarter and 30.8% in the same period of the prior year. The flat margin in the fourth quarter primarily reflects a tough comp in 2015. For the full year, gross profit increased 20% to $516 million, driven primarily by our organic and acquisition sales growth. Gross margin for the year increased by 170 basis points to 31.3% compared to 29.6% for the full year 2015. Our initiatives in category management and pricing were the primary contributors to the increase, each accounting for approximately half of the improvement. Mix did not have a significant impact on gross margin for the quarter or the year. Acquisitions had a negligible impact on gross margin in the quarter and a negative 30 basis points impact on the gross margin for the year.
Selling, general and administrative expenses or SG&A increased to $116 million in the fourth quarter from $111 million in the same period last year. The increase in SG&A was primarily attributable to our growth through acquisitions, partially offset by fewer selling days. SG&A as a percentage of net sales decreased to 32.1% from 32.6% over the same time period. In 2016, we benefited from normal levels of marketing expense and professional fees following our brand launch and IPO preparation expense in 2015. For the full year, SG&A increased to $447 million from $373 million in 2015. SG&A as a percentage of net sales increased to 27.1% for the 2016 fiscal year as compared to 25.7% for the 2015 fiscal year. The increase in SG&A was primarily attributable to our acquisitions, transition costs associated with becoming a public company and our debt refinancing and higher personnel costs as we completed the build-out of our functional teams.
We recorded a net loss for the fourth quarter of $5.6 million or $0.14 per share compared to a loss of $5.9 million or $1.39 per share during the same period last year. Net income for 2016 fiscal year was $30.6 million compared to $28.9 million in 2015. The increase was primarily attributable to our growth in net sales and gross margin, partially offset by higher SG&A and interest expense. On a per share basis, we recorded a loss of $3.01 for the year. The results for the year reflect the extraordinary dividend paid to the preferred shareholders. Excluding that payment, we would have recorded a gain on a per share basis. The weighted average common shares outstanding used in the earnings per share calculation were 39.6 million for the fourth quarter and 30.3 million for the full year.
The effective tax rate for the quarter was 42.3% as compared to 31.4% for the fourth quarter 2015. This change is due primarily to the impact of state income taxes in fiscal 2016. The effective tax rate for the full year was 41.0% as compared to 40.3% for the prior year. The increase in the effective tax rate was primarily due to nondeductible transaction costs related to our 2016 stock offerings. Adjusted EBITDA decreased slightly to $11.2 million for the fourth quarter compared to $11.9 million for the same period in the prior year. For the year, adjusted EBITDA increased 26% to $134 million compared to $107 million in the prior year. Adjusted EBITDA margin increased by 80 basis points to 8.1%. Our adjusted EBITDA improvement primarily reflects our continued sales growth and margin improvement.
Now I'd like to provide a brief update on our balance sheet and cash flow statement as shown on Slide 9. Net working capital increased to $305 million at the end of 2016 fiscal year as compared to $297 million at the end of the 2015 fiscal year. The increase in net working capital reflects the continued growth of our business. As a percentage of sales, however, net working capital decreased to 19% of sales compared to 20% of sales in 2015. This reflects early improvements coming through from our supply chain initiatives.
Net debt at the end of the year was $370 million, and leverage at the end of the year was 2.8x our annual adjusted EBITDA of $134 million. In our IPO registration statement, we presented a pro forma balance sheet for year-end 2015, which yielded a leverage ratio of 3.3x our annual adjusted EBITDA of $106.5 million. Our strategy is to continue to grow through acquisition while keeping our leverage at a manageable level. I am pleased to say with our strong cash flow, which includes good performance from the acquired companies, we accomplished that in 2016 and our leverage is now within our long-term target range of 2x to 3x adjusted EBITDA.
Cash flow from operations was $73 million for the 2016 fiscal year compared to $71 million for the 2015 fiscal year. The improvement in operating cash flow reflects our growth in EBITDA, partially offset by the increase in interest expense and working capital. Free cash flow, which is defined as cash flow from operations minus CapEx, was $64 million and was 209% of net income. We've made investments of $75 million during the year, including $66 million for acquisitions and $9 million for capital expenditures. This compares to $111 million of investments in 2015, including $101 million for acquisitions and $10 million for capital expenditures. We invested less in acquisitions in 2016, primarily because we did not have a single acquisition as large as Shemin, one of the largest companies in this industry.
In summary, our capital structure and our ability to generate cash provide us with the flexibility to execute our growth strategy, including funding of our acquisitions. I will now turn the call over to Pascal for an update on SiteOne's acquisition strategy.