It puts us on a path for another strong year in 2022.
When we execute, we expect to unlock $850 million of additional through cycle EBITDA through state-of-the-art mini mill steelmaking and finishing line capabilities.
And we will have further differentiated our sustainability advantages by customers as we continue to deliver against our responsible steel and 2050 decarbonization objectives while growing our offering of sustainable steel solutions, including verdeX.
So we will continue to buy back our own stock and are pleased to announce an incremental $500 million authorization.
We delivered our best safety and environmental performance on record and continue our progress toward our ambitious 2030 and 2050 carbon reduction goals.
We moved quickly and our well-timed acquisition allowed us to capture the remarkable earnings power of Big River Steel in 2021, including nearly $1.4 billion of EBITDA and 39% EBITDA margin.
We ended the year with adjusted EBITDA of approximately $5.6 billion and an adjusted EBITDA margin of 28%.
This translated into record free cash flow generation of approximately $3.2 billion, including over $1 billion in the fourth quarter alone.
Adjusted earnings per share in the quarter was $3.64 per share and was significantly impacted by a noncash year-end true-up to our tax valuation allowance.
Our strong performance in 2021 allowed us to transform our balance sheet by repaying over $3 billion in debt in the year and ending the year with 0.7 times leverage.
The remaining debt on the balance sheet is manageable with over 80% due until 2029 and beyond.
And we're also ending the year with nearly $5 billion of liquidity, including over $2.5 billion of cash.
In our flat-rolled segment, we delivered record EBITDA and EBITDA margin in 2021 of over $3.1 billion and 25%, respectively.
In the fourth quarter alone, we generated over $1 billion of EBITDA and an EBITDA margin of 30%.
2021 delivered record EBITDA and EBITDA margin of nearly $1.4 billion and 39%, respectively.
This included $406 million of EBITDA in the fourth quarter and an industry-leading 41% EBITDA margin.
The fourth quarter marked the second consecutive quarter of $400 million plus of EBITDA and over 40% EBITDA margins.
EBITDA was nearly $1.1 billion for the year or 25% EBITDA margin.
Lastly, our tubular segment reported nearly $50 million of EBITDA in 2021, including $42 million in the fourth quarter alone.
Auto builds in North America are expected to increase by 2 million units in 2022 and accelerate as the year progresses.
In Europe, pricing has already stabilized close to $1,000 per ton and our order book has been steady.
This is in addition to our existing $300 million authorization announced in October 2021, of which approximately $200 million has been repurchased to date under the existing authorization.
imports of sheet steel increased over 70% to a six-year high.
As we continue to execute our strategy, we are targeting a through-cycle total debt-to-EBITDA leverage metric of 3 to 3.5 times.
2 and the strategic investments we are making in non-grain-oriented electrical steel and galvanizing capability at Big River Steel by maintaining a cash position no less than our next 12-month capex.
For us, best for all starts with enhancing our focus on expanding our competitive advantages: low-cost iron ore, mini mill steelmaking, and best-in-class fishing capabilities, and by returning and by delivering returns of at least 15%.
Last quarter, we were pleased to announce our restored $0.05 per share quarterly dividend, and our first priority for direct returns is to maintain that dividend policy.
As mentioned earlier, I am pleased to say that our Board has authorized a new and incremental repurchase program of $500 million.

Summary:
It puts us on a path for another strong year in 2022.
So we will continue to buy back our own stock and are pleased to announce an incremental $500 million authorization.
Adjusted earnings per share in the quarter was $3.64 per share and was significantly impacted by a noncash year-end true-up to our tax valuation allowance.
As mentioned earlier, I am pleased to say that our Board has authorized a new and incremental repurchase program of $500 million.