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Exhibit 99.1 AAON® AAON REPORTS EARNINGS & BACKLOG FOR THE FIRST QUARTER OF 2021 TULSA , OK , May 6 , 2021 - AAON , INC . ( NASDAQ - AAON ) , today announced its results for the first quarter of 2021 . Financial Highlights : Three Months Ended March 31 , Net sales Gross profit Gross profit % Selling , general and admin . expenses SG & A % Net income Net income % Effective Tax Rate Earnings per diluted share Diluted average shares Backlog Cash & cash equivalents & restricted cash Total current liabilities $ $ 2021 28.6 % ( in thousands , except share and per share data ) 115,788 $ 137,483 33,157 42,947 14,696 12.7 % 1 16,376 14.1 % 11.4 % 0.30 53,814,644 March 31 , 2021 $ 96,733 97,772 66,679 $ 2020 ( in thousands ) 31.2 % 15,214 11.1 % 21,853 15.9 % 21.5 % 0.41 52,871,419 December 31 , 2020 % Change 74,417 82,288 59,033 ( 15.8 ) % ( 22.8 ) % ( 3.4 ) % ( 25.1 ) % ( 26.8 ) % 1.8 % % Change 30.0 % 18.8 % 13.0 % Net sales for the first quarter of 2021 decreased 15.8 % to $ 115.8 million from $ 137.5 million in the first quarter of 2020. The year over year decline in net sales was partially attributable to fewer production days due to an extended holiday shutdown in early January and winter storm in February and is a reflection of our markets temporarily moderating at the end of 2020 . Moreover , the prior year quarter was an all time record for the Company creating a tough relative comparison . The Company reported diluted EPS of $ 0.30 , down 26.8 % from $ 0.41 in the prior year period . The decline in EPS was largely due to the lower recognized revenue , partially offset by a lower effective tax rate . The lower tax rate compared to a year ago mainly related to a $ 1.8 million increase in excess tax benefits associated with stock awards . The Company finished the quarter with a backlog of $ 96.7 million , down from $ 119.6 million one year ago but up from $ 74.4 million at the end of 2020. The sequential improvement reflects the improved demand that we experienced throughout the first quarter . New bookings in the quarter increased 21 % compared to the same period one year ago . Demand has continued to strengthen through April . As of May 1 , 2021 , backlog was approximately $ 104.5 million . Gary Fields , President and CEO , noted " As we've mentioned in our prior releases , we were previously overwhelmed with customer orders and did not have the capacity to handle all these orders which lead to lengthy lead times in 2019. We spent most of that year adding several Salvagnini sheet metal fabrication machines and rearranging our production lines for more efficient production . In Longview , we started construction of our 224,000 square feet building which also housed additional Salvagninis and was completed in early 2021. As all this was happening , we had our lead times come down which resulted in a