An investor company purchased $767,000 of 5% bonds from the investee company on January 1, 2020, with interest payable on December 31. The bonds were classified as Available-for-Sale. The bonds sold for $593,400. Using the effective-interest method, the investor company revised the Available-for-Sale Debt Securities account on December 31, 2020 and December 31, 2021 by the amortized discount/premium of $6,210. and $8,400, respectively. At December 31, 2020, the fair value of the investee company bonds was $435,000.

At December 31, 2021, the fair value of the investee company bonds was $657,000.

What is the amount of unrealized holding gain/loss related to this investment in 2021?