Our acquisitions may include contingent consideration as part of the purchase price under which we will make future payments to the seller upon the achievement of certain benchmarks. The fair value of the contingent consideration is estimated as of the acquisition date at the present value of the expected contingent payments to be made using a probability-weighted discounted cash flow model for probabilities of possible future payments. The present value of the expected future payouts is accreted to interest expense over the period. The fair value estimates use unobservable inputs that reflect our own assumptions as to the ability of the acquired business to meet the targeted benchmarks and discount rates used in the calculations. The unobservable inputs are defined in FASB ASC Topic 820, as Level 3 inputs discussed in detail in Note 15.

We review the probabilities of possible future payments to the estimated fair value of any contingent consideration on a quarterly basis over the period. Actual results are compared to the estimates and probabilities of achievement used in our forecasts. Should actual results of the acquired business increase or decrease as compared to our estimates and assumptions, the estimated fair value of the contingent consideration liability will increase or decrease, up to the contracted limit, as applicable. Changes in the estimated fair value of the contingent consideration are reflected in our results of operations in the period in which they are identified. Changes in the estimated fair value of the contingent consideration may materially impact and cause volatility in our operating results.

We acquired the InvestmentHouse.com website and the related financial newsletter assets and deferred subscription liabilities on June 6, 2019. We paid $0.6 million in cash upon closing and may pay an additional incentive payment equal to 10% of revenue earned in excess of a predetermined amount during the incentive period ending May 31, 2020. Using a probability-weighted discounted cash flow model based on our own assumptions as to the ability of InvestmentHouse.com to achieve revenue in excess of the targets at the time of closing, we estimated the fair value of the contingent consideration to be $2,500, which approximated the present value based on the period of less than twelve months.

We will review the fair value of the contingent consideration quarterly over the period to compare actual revenues achieved and projected to the estimated revenues used in our forecasts. Any changes in the estimated fair value of the contingent consideration will be reflected in our results of operations in the period they are identified.

We acquired the Hilary Kramer Financial Newsletters and related assets on August 9, 2018. We paid $0.4 million in cash upon closing and may pay up to an additional $0.1 million in contingent consideration over the next two years upon the achievement of income benchmarks as part of the purchase agreement. Using a probability-weighted discounted cash flow model based on our own assumptions as to the ability of Hilary Kramer Financial Newsletters to achieve the income targets at the time of closing, we estimated the fair value of the contingent consideration to be $40,617, which was recorded at the discounted present value of $39,360. The discount will be accreted to interest expense over the two year period.

We review the fair value of the contingent consideration quarterly over the period to compare actual revenues achieved and projected to the estimated revenues used in our forecasts. Any changes in the estimated fair value of the contingent consideration will be reflected in our results of operations in the period they are identified, up to the maximum future value outstanding under the contract of $0.1 million. There were no changes in our estimates of the fair value of the contingent consideration as of the six month period ended June 30, 2019.

We acquired the Just1Word mobile application and related assets on August 7, 2018. We paid $0.3 million in cash upon closing and may pay up to an additional $0.1 million in contingent consideration over the next two years upon the achievement of income benchmarks as part of the purchase agreement. Using a probability-weighted discounted cash flow model based on our own assumptions as to the ability of Just1Word to achieve the income targets at the time of closing, we estimated the fair value of the contingent consideration to be $12,750, which was recorded at the discounted present value of $12,212. The discount will be accreted to interest expense over the two year period.

We review the fair value of the contingent consideration quarterly over the period to compare actual revenues achieved and projected to the estimated revenues used in our forecasts. Any changes in the estimated fair value of the contingent consideration will be reflected in our results of operations in the period they are identified, up to the maximum future value outstanding under the contract of $0.1 million. We recorded an increase of $4,000 in the estimated fair value of the contingent consideration that is reflected in our results of operations for the period ended December 31, 2018. There were no changes in our estimates of the fair value of the contingent consideration as of the six month period ended June 30, 2019.