Richard McPhail
Chief Financial Officer and Executive Vice President at Home Depot
Thank you, Ted, and good morning, everyone. In the fourth quarter, total sales were $35.7 billion, an increase of approximately $3.5 billion or 10% -- 10.7% from last year. Our total company comps were positive 8.1% for the quarter with positive comps of 7.3% in November, 10.2% in December and 7% in January. Comps in the U.S. were positive 7.6% for the quarter with positive comps of 7.2% in November, 10.9% in December and 5.4% in January. Our results in the fourth quarter were once again driven by broad-based strength across the business and our geographies. All 19 U.S. regions posted positive comps, and Canada and Mexico both posted double-digit positive comps in the fourth quarter.
For the year, our sales totaled a record $151.2 billion, with sales growth of $19 billion or 14.4% versus fiscal 2020. For the year, total company comp sales increased 11.4%, and U.S. comp sales increased 10.7%. In the fourth quarter, our gross margin was 33.2%, a decrease of approximately 35 basis points from last year. And for the year, our gross margin was 33.6%, a decrease of approximately 30 basis points from last year, primarily driven by product mix and investments in our supply chain network. During the fourth quarter, operating expenses were approximately 19.7% of sales, representing a decrease of approximately 120 basis points from last year.
Our operating leverage during the fourth quarter reflects comparisons against significant COVID-related expenses that we incurred in the fourth quarter of 2020 to support our associates, the anniversarying of $110 million of nonrecurring expenses related to the completion of the HD Supply acquisition in the fourth quarter of 2020, and solid expense management for the quarter. During the fourth quarter of fiscal 2021, we also incurred approximately $125 million of COVID-related expenses. For the year, operating expenses were approximately 18.4% of sales, representing a decrease of approximately 170 basis points from fiscal 2020.
Our operating expense leverage in fiscal 2021 reflects a decrease in our COVID-related costs compared to last year, partially offset by wage actions taken at the end of 2020 as well as throughout 2021. Our operating expenses for the year included a consistent level of investment in our business, which we intend to continue. For the year, we are very pleased with the operating expense leverage we were able to deliver. Our operating margin for the fourth quarter was approximately 13.5% and for the year was approximately 15.2%. Interest and other expense for the fourth quarter was essentially flat with last year. In the fourth quarter, our effective tax rate was 25.5%, and for fiscal 2021, was 24.4%.
Our diluted earnings per share for the fourth quarter were $3.21, an increase of 21.1% compared to the fourth quarter of 2020. Diluted earnings per share for fiscal 2021 were $15.53, an increase of 30.1% compared to fiscal 2020. During the year, we opened seven new stores and added 14 new stores through a small acquisition, bringing our store count to 2,317 at the end of fiscal 2021. Retail selling square footage was approximately 241 million square feet at the end of fiscal 2021. Total sales per retail square foot were approximately $605 in fiscal 2021, the highest in our company's history. At the end of the quarter, merchandise inventories were $22.1 billion, an increase of $5.4 billion versus last year.
And inventory turns were 5.2 times, down from 5.8 times from the same period last year. Moving on to capital allocation. During the fourth quarter, we invested approximately $830 million back into our business in the form of capital expenditures. This brings total capital expenditures for fiscal 2021 to $2.6 billion. During the year, we paid approximately $7 billion of dividends to our shareholders. We look to grow our dividend every year as we grow earnings. And today, we announced our Board of Directors increased our quarterly dividend by 15% to $1.90 per share, which equates to an annual dividend of $7.60. And finally, during fiscal 2021, we returned approximately $15 billion to our shareholders in the form of share repurchases, including $4.5 billion in the fourth quarter.
Computed on the average of beginning and ending long-term debt and equity for the trailing 12 months, return on invested capital was 44.7%, up from 40.8% in the fourth quarter of fiscal 2020. Now I'll comment on our outlook for 2022. The broader housing environment continues to be supportive of home improvement. Demand for homes continues to be strong, and existing home inventory available for sale remains near record lows, resulting in support for continued home price appreciation. On average, homeowners' balance sheets continue to strengthen as the aggregate value of U.S. home equity grew approximately 35% or $6.5 trillion since the first quarter of 2019.
The housing stock continues to age, and customers tell us the demand for home improvement projects of all sizes is healthy. While we are encouraged by the consistent and resilient demand we've seen for home improvement, broader uncertainty remains with respect to the impact of inflation, supply chain dynamics and how consumer spending will evolve through the year. Given these factors, establishing full year 2022 guidance based on macroeconomic fundamentals remains challenging. As a result, our fiscal 2022 guidance is based on the run rate of dollar demand we have observed over the last two quarters. We adjust this dollar run rate for our historical seasonality to calculate our sales outlook for 2022.
Based on this approach and assuming there are no material shifts in demand, we calculate that sales growth and comp sales growth will be slightly positive for fiscal 2022. We would expect our fiscal 2022 operating margin to be flat to 2021. And we would expect low single-digit percentage growth in diluted earnings per share compared to fiscal 2021. Over the course of fiscal 2022, we plan to invest approximately $3 billion back into our business in the form of capital expenditures, in line with our annual expectation of approximately 2% of sales going forward.
We believe that we have positioned ourselves to meet the needs of our customers in any environment, as evidenced by our results. The investments we've made in our business have enabled agility in our operating model. As we look forward, we will continue to invest to strengthen our position with our customers, leverage our scale and low-cost position to drive growth faster than the market and deliver shareholder value.
With that, I'll hand it back to Craig.