But I'd like to highlight the 7% organic revenue growth that we reported, reflecting broad and strong demand in key markets such as semiconductors, smartphones, water, residential construction and automotive.
As part of the transaction, we received 7.3 billion cash from IFF and retired slightly more than 197 million coupon shares, or about 27% of our outstanding shares at the time with no cash outlay.
We strengthened our balance sheet during the quarter by paying down our $3 billion term loan, and we will redeem $2 billion of our long-term debt later this month.
In line with our balanced approach, we returned about 660 million of capital to shareholders during the first quarter through share repurchases and dividends.
Under our existing share buyback program, we executed 500 million in share repurchases during the first quarter.
As a reminder, we have about 500 million of repurchase authorization remaining under that program, which we intend to utilize by June 1 of this year.
Earlier this quarter, we also announced that our board of directors authorized a new 1.5 billion share buyback program, which expires on June 30, 2022.
With respect to dividends, we returned about 160 million in cash to shareholders during the quarter.
As we previously mentioned, going forward, we will target a payout ratio between 35 and 45%.
In March, we announced a definitive agreement to acquire Laird Performance Materials for $2.3 billion.
We anticipate receiving more than 900 million in gross proceeds from those divestitures, and we expect those transactions to close in the second half of this year.
With respect to the automotive end market, demand is well above the lows of 2020 but not yet back to 2019 levels, which sold 22.9 million vehicles produced in the first quarter and nearly 90 million units for the year.
Even where we participate in the value chain within M&M, I think it's important to note that our first quarter engineering polymers volumes were not materially affected by the chip shortages as our demand from the Tier 1 and Tier 2 suppliers was not lessened as a result of the chip shortage.
This supply situation is gradually improving while we anticipate several critical products will continue to constrain our production through the end of the second quarter.
Collectively, these two markets account for approximately 20% of our total company sales.
Sequentially, our sales in the aero and oil and gas were up over 40%.
Net sales of 4 billion were up 8% versus the first quarter of 2020, up 7% on an organic basis.
Overall sales growth was driven by strong volume, up 7% versus first quarter of last year, with volume increases in all three reporting segments.
Currency provided a 3% tailwind in the quarter led by the euro.
Portfolio was a 2% headwind, primarily due to the sale of the trichlorosilane business last year.
Sales were up in all three segments, with E&I, M&M and W&P reflecting organic growth of 14%, 8% and 1%, respectively.
On a regional basis, organic sales were up 20% in Asia Pacific, our largest region from a sales perspective, with strong results in all three reporting segments.
Partially offsetting gains in Asia Pacific were organic sales decline in the U.S. and Canada and EMEA of 4 and 2%, respectively.
From an earnings perspective, we delivered operating EBITDA of 1.05 billion and adjusted earnings per share of $0.91 per share, up 15 and 90%, respectively.
Volume gains, as well as benefit from prior-year cost initiatives and currency drove 160 basis points of operating EBITDA margin expansion and 1.9 times operating leverage.
Incremental margins for the quarter were 46%.
Our total company gross margin for the quarter was 36.8%, flat on a year-over-year basis.
Gross margin expanded about 280 basis points sequentially, with margin improvement in all three segments.
From a segment perspective, E&I delivered operating EBITDA margin of 33.5% and 420 basis points of margin expansion versus the year-ago period on strong volume growth and a onetime discrete gain related to an asset sale.
Excluding the benefit of the asset sale, operating EBITDA margin would have been 31.7%, a year-over-year improvement of 240 basis points.
M&M delivered operating EBITDA margins of 22.9% and 320 basis points of margin expansion versus the year ago period on higher volumes and savings from productivity actions.
For the quarter, cash flow from operating activities and free cash flow were 378 million and 95 million, respectively.
In addition, cash flow and free cash flow conversion was negatively impacted by a working capital headwind of about 300 million, led by higher accounts receivable balances, which were up in line with sales.
For the year, we continue to target free cash flow conversion of greater than 90%.
Leading the way for the quarter was E&I with 15% volume growth, which had a record quarter.
Shelter solutions had low single-digit organic growth versus the year ago period, reflecting high single-digit organic growth in residential construction and retail channels for do-it-yourself application, offset partially by softness in commercial construction market.
Also contributing to strong first-quarter top line growth was continued recovery of the global automotive market, which represents about 60% of our M&M segment from an end market perspective.
The most recent estimate of 1Q global auto builds were about 20.3 million units toward the quarter, up approximately 14% versus the first quarter of last year.
As a result, volume in our performance resins business was up over 20% versus the year-ago period.
These specialized materials, along with adhesive growth, helped drive over 20% organic growth in advanced solutions growth in the year ago period.
I mentioned that adjusted earnings per share for the quarter of $0.91 was up 90% versus the prior year.
The lower share count provided a $0.16 benefit versus the prior year.
Excluding the lower share count, adjusted earnings per share growth was still significant, up 56% versus the prior year.
Higher segment earnings provided a $0.13 tailwind in the quarter versus the prior year, along with benefits this year with a lower base tax rate and reduced interest expense.
Our base tax rate for the quarter of 19.4% was lower than forecasted as a result of a few discrete tax benefits in the quarter.
For the full-year 2021, we now expect our base tax rate to be in the range of 21 to 22%, down slightly from the 21 to 23% that we previously estimated at the beginning of the year.
However, I would like to point out that net working capital productivity gains of about 600 million that we have made in the first quarter of last year, decreasing net working capital for about 3.5 billion at March 2020 to 2.9 billion at March of 2021.
We started the year with $15.6 billion in current debt.
And as Ed mentioned, we paid down our $3 billion term loan in February, and we will pay down $2 billion of debt later this month.
Our cash generated from operations last year put us in a strong cash position coming into this year, and that balance grew with a $7.3 billion special cash payment from the transaction with IFF.
In addition, we expect to receive over 900 million in gross proceeds this year from the previously announced sale of the non-core businesses.
Along with our plan for internal investment this year, we plan to grow through targeted M&A in areas of secular growth and will fund the $2.3 billion planned acquisition of Laird performance materials with cash on hand.
Along with our dividend policy, we completed 500 million of share repurchases in the first quarter at an average price of about $73 per share and will remain opportunistic with our remaining share repurchase authorization throughout the rest of the year.
On a go-forward basis, our target run and maintain cash balance is about $1.5 billion.
And from a leverage perspective, our net debt-to-EBITDA target remains at 2.75 times.
We are raising our full-year guidance range for net sales, operating EBITDA and adjusted EPS.
At the midpoint of the range provided, we now expect net sales for the year to be about $15.8 billion, which reflects year-over-year growth of 10%, up from our previous estimate of 8% growth.
We expect to improve leverage and now expect operating EBITDA for the year to be about 4.03 billion, at the midpoint of the range provided, a year-over-year increase of 17%.
We are also raising our adjusted earnings per share range for the full year by $0.30 per share and now expect adjusted earnings per share of $3.67 per share, at the midpoint of the range provided.
For the second-quarter 2021, we expect net sales to be about 3.975 billion, and we expect the operating EBITDA to be about $1 billion, both at the midpoints of the ranges provided and both well above results in the second quarter last year.
At the midpoint of the range provided, we expect adjusted earnings per share for the second quarter of 2021 of $0.94 per share, which now reflects the full reduction in shares resulting from the N&B exchange offer and our weighted average shares.

Summary:
This supply situation is gradually improving while we anticipate several critical products will continue to constrain our production through the end of the second quarter.
From an earnings perspective, we delivered operating EBITDA of 1.05 billion and adjusted earnings per share of $0.91 per share, up 15 and 90%, respectively.
Shelter solutions had low single-digit organic growth versus the year ago period, reflecting high single-digit organic growth in residential construction and retail channels for do-it-yourself application, offset partially by softness in commercial construction market.
We are raising our full-year guidance range for net sales, operating EBITDA and adjusted EPS.
We expect to improve leverage and now expect operating EBITDA for the year to be about 4.03 billion, at the midpoint of the range provided, a year-over-year increase of 17%.
We are also raising our adjusted earnings per share range for the full year by $0.30 per share and now expect adjusted earnings per share of $3.67 per share, at the midpoint of the range provided.