Note 4 — Servicing Assets

The changes in servicing assets for the years ended December 31, 2019 and 2018 were as follows:

At December 31, 2019 and 2018, we serviced the loans sold to unaffiliated parties in the amount of $422.3 million and $448.6 million, respectively. These represent loans that have been sold for which the Bank continues to provide servicing. These loans are maintained off balance sheet and are not included in the loans receivable balance. All of the loans being serviced were SBA loans.

The Company recorded servicing fee income of $4.4 million for the year ended December 31, 2019, and $4.7 million each of the years ended December 31, 2018 and 2017, respectively. Net amortization expense was $2.8 million, $2.6 million and $2.4 million for the years ended December 31, 2019, 2018 and 2017, respectively. Servicing fee income, net of amortization of servicing assets and liabilities, is included in other operating income in the consolidated statements of income.

The fair value of servicing rights was $7.0 million at year-end 2019. Fair value at year-end 2019 was determined using the discount rates ranging from 7.7 percent to 21.4 percent, prepayment speeds ranging from 1.8 percent to 15.6 percent, depending on the stratification of the specific right.