Credit Rating
| Credit Rating Agency |
 NICE Credit Information Service |
 Korea Ratings
|
 Korea Investors Service |
 Fitch Ratings
|
 Moody’s
|
 S&P
|
|---|---|---|---|---|---|---|
| 2024 | AA+ | AA+ | AA+ | A | A2 | A |
| 2023 | AA+ | AA+ | AA+ | A | A2 | A |
| 2022 | AA+ | AA+ | AA+ | A | A2 | A |
| 2021 | AAA | AAA | AAA | A | A2 | A |
| 2020 | AAA | AAA | AAA | A | A2 | - |
| 2019 | AAA | AAA | AAA | A+ | A1 | - |
| 2018 | AAA | AAA | AAA | A+ | A1 | - |
| 2017 | AAA | AAA | AAA | - | - | - |
| 2016 | AAA | AAA | AAA | - | - | - |
| 2015 | AAA | AAA | AAA | - | - | - |
| 2014 | AAA | AAA | AAA | - | - | - |
| 2013 | AAA | AAA | AAA | - | - | - |
| 2012 | AAA | AAA | AAA | - | - | - |
| 2011 | AAA | AAA | AAA | - | - | - |