13. BUSINESS COMBINATIONS  As part of our strategy to supplement our organic growth and expand our access to additional markets and products, we completed one acquisition in 2019, and two acquisitions to date in 2020. Each acquisition was accounted for as a business combination under ASC 805, Business Combinations. Acquisition costs for the three months ended March 31, 2020 and 2019, were $0.2 million and $0.1 million, respectively. Acquisition costs are included in selling, general, and administrative expense in our condensed consolidated statements of operations.  Acquisitions  On July 15, 2019, we acquired Viking, an insulation company located in Burbank, California. The purchase price of approximately $7.7 million was funded by cash on hand of $6.5 million and contingent consideration of $1.2 million.  On February 20, 2020, we acquired Cooper, a commercial glass company serving the Memphis market. The purchase price of approximately $11.5 million was funded by cash on hand of $10.5 million and contingent consideration of $1.0 million. We recognized goodwill of $6.4 million in connection with this acquisition during the quarter ended March 31, 2020.  On February 24, 2020, we acquired Hunter, a residential insulation company located in Long Island, New York. The purchase price of approximately $9.1 million was funded by cash on hand. We recognized goodwill of $5.5 million in connection with this acquisition during the quarter ended March 31, 2020.  Contingent Consideration  On February 27, 2017, we acquired substantially all of the assets of EcoFoam, a residential and light commercial insulation installation company with locations in Colorado Springs and Denver, Colorado. The purchase price of approximately $22.3 million was funded by cash on hand of $20.2 million and contingent consideration of $2.1 million. The contingent consideration arrangement requires additional consideration to be paid by TopBuild to the sellers of EcoFoam based on EcoFoams attainment of annual revenue targets over a three-year period. The total amount of undiscounted contingent consideration which TopBuild is required to pay under the arrangement is $2.5 million. The fair value of $2.1 million contingent consideration recognized on the acquisition date was estimated by applying the income approach using discounted cash flows. That measure is based on significant Level 3 inputs not observable in the market. The significant assumption includes a discount rate of 9.5% . Changes in the fair value measurement each period reflect the passage of time as well as the impact of adjustments, if any, to the likelihood of achieving the specified targets. We made contingent payments of $0.8 million in the second quarters of 2019 and 2018. We will make the final payment of $0.8 million in the second quarter of 2020.  The acquisition of Viking included a contingent consideration arrangement that requires additional consideration to be paid by TopBuild based on the achievement of annual gross revenue targets over a three-year period. The range of undiscounted amounts TopBuild may be required to pay under the contingent consideration agreement is between zero and $1.5 million. The fair value of the contingent consideration recognized on the acquisition date of $1.2 million was estimated by applying the income approach using discounted cash flows. That measure is based on significant Level 3 inputs not observable in the market. The significant assumption includes a discount rate of 10.0% . Changes in the fair value measurement each period reflect the passage of time as well as the impact of adjustments, if any, to the likelihood of achieving the specified targets.  The acquisition of Cooper includes a contingent consideration arrangement that requires additional consideration to be paid by TopBuild based on the achievement of annual gross revenue targets over a two-year period. The range of undiscounted amounts TopBuild may be required to pay under the contingent consideration agreement is between zero and $1.0 million, which also represents the fair value recognized on the acquisition date.  The following table presents the fair value of contingent consideration, in thousands:             EcoFoam Viking  Cooper Date of Acquisition  February 27, 2017  July 15, 2019  February 20, 2020 Fair value of contingent consideration recognized at acquisition date  $ 2,110  $ 1,243  $ 1,000           Contingent consideration at December 31, 2019  $ 822  $ 1,304  $  Additions         1,000 Change in fair value of contingent consideration during the three months ended March 31, 2020   19   32    Payment of contingent consideration during the three months ended March 31, 2020          Liability balance for contingent consideration at March 31, 2020  $ 841  $ 1,336  $ 1,000