David Little
Analyst · Stephens
Good morning. Thank you, Ken, and thanks to everyone for joining us today on our 2021 fourth quarter and year-end conference call. I will begin today with some perspectives on our fourth quarter and year-end results, current industry conditions and our position going forward. Ken will then take you through the key financial details after my remarks. After his prepared comments, we will open for Q&A.
As we all know, everyone continues to navigate through COVID and COVID-related challenges for 2021, and I am proud of the courage, compassion and commitment demonstrated by our DXPeople throughout the year. There is no question 2021 was an extraordinary year. It continued to remain challenging for us, our customers, our DXPeople, our suppliers and our communities. But even in an incredible dynamic market environment, DXPeople came together, we stayed true to our strategy, remain customer-driven, and though we still have a lot of work to do, I am proud of the fact that we delivered strong results for our shareholders.
DXP started fiscal 2021 believing financial results were not going to become easy and we were going to have to take market share where we could. The pace and magnitude of recovery would vary greatly from geography, customer type and end markets. This largely proved to be true as the economy continued to recover from the short, but deep recession the marked the pandemic's early months and days. The subsequent robust growth that followed in certain markets began to put enormous pressure on the supply chain, triggering levels of inflation not seen in decades. By year-end, interest rate hikes were widely expected. Markets entered into a new uncertainty.
While we don't expect fiscal 2022 to look like 2021, DXP's confidence is as strong as it ever has been. Our strategy is working. We continue to be customer-driven experts, sourcing, providing, servicing our customers, as they navigate whatever the outcome year holds.
In fiscal 2021, we soundly executed on diversifying our end markets with a focus on water and wastewater and other industrial markets, continuing to do acquisitions, adding 3 great companies during the year including Carter & Verplanck, Process Machinery and Premier Water. Executing, we executed on share repurchase program and growing organically in the second half of 2021, delivering second half organic sales growth of 13%.
Our strategy has always been to combine financial strength, talent, resources, technology and capabilities of a large company with the fast, flexible and entrepreneurial capabilities of our local businesses to deliver superior value to our customers and our suppliers while providing better growth opportunities for our DXP people. We continue to believe in this approach and look to renew our commitment to people, processes and resources and technology as we scale DXP and we remain focused on doubling the size of our business over the next 3 to 5 years.
From a sales per business day standpoint, DXP experienced continued improvement throughout the year, with Q1 averaging 3.9 million sales per day and ending Q4 averaging 4.8 million sales per business day or an improvement of 23.1% from Q1 to Q4. While we did experience some softness during the summer months, from August through the end of December, we consistently performed above our 2021 sales per day average of 4.5 million sales per day. Our fourth quarter results reflect sequential sales growth and improvements in our end markets and industry indicators, including our PMI and our metalworking indexes. Oil and gas also started to see signs of firming and DXP experienced sequential increases in our related backlog and IPS expected -- experienced 2 sequential quarters of organic growth through Q4.
Total DXP sales for Q4 were $293.1 million or $4.8 million per business day. Our profits for the quarter were impacted by a sequential decline in gross margins as well as an increase in SG&A associated -- expenses associated with auditor transition and related items, which Kent will review during his comments.
However, in the midst of continued change in growth, our year-over-year earnings showed improvement and resilience as we grew diluted earnings per share 13.9% to $0.83 per share on a year-over-year basis.
Thank you to our 2,841 DXPeople for your hard work and dedication and finishing the year as strongly as possible. It is always my pleasure to share our fourth quarter and year-end results on your behalf.
In terms of cash flow and liquidity, we generated $32.7 million of free cash flow versus a record of $101 million of free cash flow in 2020, which reflects the turning of the business and investing in related working capital as the business begins to turn positive during the second half of the year. This, combined with flexible capital structure, plus us in a position where we could keep executing on our acquisition strategy, as well as return capital to our shareholders via opportunistic share repurchases. As we discussed at the back end of 2020, acquisitions have continued to diversify our end market exposure and position us well for a rebounding economy as we are excited about 2022 and the growth we expect to see both organically and through acquisitions as we continue to have a strong pipeline of opportunities.
We are excited to have 3 new companies join us during the year 2021, on top of the 4 we completed at the end of 2020 or essentially the beginning of 2021. Carter & Verplanck, Process Machinery, Premier Water have been great additions to the DXP family. That is 7 acquisitions over the last 12 months, including APO Pumps & Compressors, Corporate Equipment Company, Pumping Systems, Inc. and Total Equipment Company. To all of you, welcome to DXP, and we are excited to have you be a part of our DXP family, and we look forward to our successes together.
DXP has continued to find ways to deliver financial results and position us well for all our stakeholders in the face of extraordinary challenges. This is evidenced by our sales growth, improved gross margins and acquisitions and the overall teamwork of the DXPeople.
We continue to build our capabilities to provide complementary set of products and services to all of our markets, which makes DXP very unique in our industry and gives us more ways to help our customer win. We also are constantly looking at reviewing opportunities where we can grow market share. We complement our strategy with a relentless drive for progress that includes business and operational initiatives, which we believe will allow us to steadily improve our performance for all our stakeholders. As we go into 2022, we are excited about the opportunities ahead and the potential DXP has to continue to scale and grow within existing and new markets.
Total DXP sales in fiscal 2021 were up 10.8% to $1.1 billion. Service centers led the way at $816 million followed by supply chain services of $158 million, and then innovative funding solutions at $140 million. The point here is acquisitions, the diversity of end markets and MRO nature of Service Centers allowed us to remain resilient. Supply Chain Services remained impacted by oil and gas and transportation-related end markets during the first half of the year, and as we move into the second, as some of these related COVID impacts began to subside. Additionally, we started more proactive sales development that translated into other growth and supply chain services in 2022.
As we discussed during Q1 through Q3, we experienced the largest organic sales decline within our Innovative Pumping Solutions business segment. IPS is tied to capital budgets and predominantly in the oil and gas industry, but we have added, through acquisitions, water and wastewater treatment project work this year, which has positively impacted the results of IPS along with improvements in cost management on our traditional business.
In terms of the strength in the IPS backlog, we have now had 2 consecutive quarters of sequential double-digit increases, and the trend looks to continue in Q1. DXP overall gross profit margins for the year were 29.5%, a 192 basis point improvement over 2020. We displayed consistent gross margin performance within IPS through the year and added accretive gross margin acquisitions. That said, IPS improved gross margins 463 basis points year-over-year in the midst of a significant decline in demand.
Overall, DXP produced EBITDA of $70.2 million or an increase of 19.1% year-over-year. EBITDA as a percent of sales was 6.3%, or an increase of 43 basis points compared to 2020.
In summary, we are pleased with our overall performance in 2021. Obviously, another excellent year that resumed the final changes, but also highlighted or accentuated certain business trends that provided us with areas to enhance and focus upon as we go into 2022. We look to continue to drive improvement in our organic sales and marketing strategies, drive future sales growth through acquisitions, and anticipate fiscal 2022 to be a strong recovery year.
Our acquisitions performed very well during 2021, contributing significantly to our growth in sales and adjusted EBITDA. We continue to expect a busy acquisition year in 2022. In 2021, we made great progress with an investment in a customer relations management system or CRM tool for our sales force, which will help our over 400 outside sales leaders bring increased value to our current customers and drive growth through new customers and increase share of wallet. We are very optimistic that our investment in digital tools and marketing can create significant competitive advantage for DXP overall through our strategic investments and initiatives. We will remain focused on providing world-class tools, processes, trainings and technology to deliver value to our customers and suppliers and to help our DXP people being more productive so they can better help our customers with.
We will continue to use whatever median the customer prefers and tailor our approach to their needs. DXP is always customer-focused, especially in the environment we have today. We're listening to the customer matters. I am very proud of how our team continues to perform in this extraordinary times. As a leading distributor of highly engineered products and services, we believe DXP remains well-positioned to support our customers and navigate this challenging period for the benefit of all our stakeholders.
I would like to sincerely thank all of our DXPeople who continue to show up to work with their passion, commitment, teamwork and selfless service. We have a tremendous team. It is an honor to overcome the collective diversity we all experienced and deliver value for all our stakeholders.
With that, I will now turn it back to Ken to review our financials in more detail.