Mills Corporation acquired as a long-term investment $400,000 of 7% bonds, dated July 1, on July 1, 2018. Mills determined that it should account for the bonds as an available-for-sale investment. The market interest rate (yield) was 6% for bonds of similar risk and maturity. Mills paid $425,124 million for the bonds. The company will receive interest semiannually on June 30 and December 31. As a result of changing market conditions, the fair value of the bonds at December 31, 2018, was $421,900. Moodys bond rating agency upgraded the risk rating of the bonds, and Mills decided to sell the investment on January 2, 2019, for $421,000. Prepare the Journal entries associated with an available for sale investment

1. July 1

Investment	400000
Premium	25124
cash		425124

2.

Cash	14000
Premium		1246
Interest income		12754

3.

Unrealized loss	1977
Investment		1977

4.

cash	421000
realized loss	2877
premium		23877
investment		398023
unrealized loss		1977

My question is why the investment in journal entry 4 is 398023 instead of 400000?

In the other example which is discount rather than premium and it has a realized gain at the end, why the investment will stay same as bond face, but this question the investment is changed?