I did this to correct outdated info on a thread elsewhere but I figured it was interesting enough to post here. This is based on Gaon sales data for 2018 releases only, so it doesn't include older albums still selling this year, doesn't include Japanese sales, nor does it include November and December releases, which wouldn't change the order of rankings for anyone other than Mamamoo and Lovelyz, and might allow Gugudan to sneak into the bottom of the second list.
Total 2018 albums per group:
1. Twice 657,235 (2 releases)
2. Red Velvet 259,004 (2)
3. Blackpink 220,802 (1)
4. GFriend 135,232 (2)
5. IZ*ONE 108,304 (1)
6. WJSN 101,420 (2)
7. Mamamoo 93,153 (2)
8. fromis_9 68,239 (3)
9. APink 63,382 (1)
10. Oh My Girl 60,282 (2)
11. Dreamcatcher 51,331 (2)
12. Loona 50,840 (1)
13. Lovelyz 49,505 (2)
14. Weki Meki 46,662 (2)
15. SNSD-Oh!GG 43,191 (1)
Total 2018 albums per group (incl. subunits/group-credited solos) *
1. Twice 657,235 (2)
2. Red Velvet 259,004 (2)
3. Blackpink 220,802 (1)
4. GFriend 135,232 (2)
5. IZ*ONE 108,304 (1)
6. WJSN 101,420 (2)
7. Mamamoo 93,153 (2)
8. Loona 83,048 (4)
9. Oh My Girl 76,340 (3)
10. fromis_9 68,239 (3)
11. APink 63,382 (1)
12. Dreamcatcher 51,331 (2)
13. Lovelyz 49,505 (2)
14. Weki Meki 46,662 (2)
15. SNSD-Oh!GG 43,191 (1)
* Loona yyxy sold 18,138, Olivia Hye sold 8,801, and Go Won sold 5,269 (the solo albums were credited to Loona, not the individual artists). The only other group in the list above that had additional subunit or solo releases is Oh My Girl, with OMG Banhana sales of 16,058. WJMK (WJSN+Weki Meki) is also technically a subunit but only released a digital single. SNSD only had a subunit release, so its numbers don't change in this ranking.
Individual 2018 albums:
1. Twice What Is Love 342,760
2. Twice Summer Nights 314,475
3. Blackpink Square Up 220,802
4. Red Velvet Summer Magic 157,028
5. IZONE Color*IZ 108,304
6. Red Velvet The Perfect Red Velvet 101,976
7. Gfriend Time for the Moon Night 81,697
8. Apink One & Six 63,382
9. WJSN WJ Please 56,264
10. Gfriend Sunny Summer 53,535
11. Loona ++ 50,840
12. Mamamoo Yellow Flower 47,022
13. Mamamoo Red Moon 46,131
14. WJSN Dream Your Dream 45,156
15. SNSD-Oh!GG Lil Touch 43,191
This was done to get updated stats on Loona, which has done really well this year, especially when including the yyxy and solo releases, and considering lack of strong sales support in SK. Other takeaways based on the total sales charts:
Total 2018 albums per group:
1. Twice 657,235 (2 releases)
2. Red Velvet 259,004 (2)
3. Blackpink 220,802 (1)
4. GFriend 135,232 (2)
5. IZ*ONE 108,304 (1)
6. WJSN 101,420 (2)
7. Mamamoo 93,153 (2)
8. fromis_9 68,239 (3)
9. APink 63,382 (1)
10. Oh My Girl 60,282 (2)
11. Dreamcatcher 51,331 (2)
12. Loona 50,840 (1)
13. Lovelyz 49,505 (2)
14. Weki Meki 46,662 (2)
15. SNSD-Oh!GG 43,191 (1)
Total 2018 albums per group (incl. subunits/group-credited solos) *
1. Twice 657,235 (2)
2. Red Velvet 259,004 (2)
3. Blackpink 220,802 (1)
4. GFriend 135,232 (2)
5. IZ*ONE 108,304 (1)
6. WJSN 101,420 (2)
7. Mamamoo 93,153 (2)
8. Loona 83,048 (4)
9. Oh My Girl 76,340 (3)
10. fromis_9 68,239 (3)
11. APink 63,382 (1)
12. Dreamcatcher 51,331 (2)
13. Lovelyz 49,505 (2)
14. Weki Meki 46,662 (2)
15. SNSD-Oh!GG 43,191 (1)
* Loona yyxy sold 18,138, Olivia Hye sold 8,801, and Go Won sold 5,269 (the solo albums were credited to Loona, not the individual artists). The only other group in the list above that had additional subunit or solo releases is Oh My Girl, with OMG Banhana sales of 16,058. WJMK (WJSN+Weki Meki) is also technically a subunit but only released a digital single. SNSD only had a subunit release, so its numbers don't change in this ranking.
Individual 2018 albums:
1. Twice What Is Love 342,760
2. Twice Summer Nights 314,475
3. Blackpink Square Up 220,802
4. Red Velvet Summer Magic 157,028
5. IZONE Color*IZ 108,304
6. Red Velvet The Perfect Red Velvet 101,976
7. Gfriend Time for the Moon Night 81,697
8. Apink One & Six 63,382
9. WJSN WJ Please 56,264
10. Gfriend Sunny Summer 53,535
11. Loona ++ 50,840
12. Mamamoo Yellow Flower 47,022
13. Mamamoo Red Moon 46,131
14. WJSN Dream Your Dream 45,156
15. SNSD-Oh!GG Lil Touch 43,191
This was done to get updated stats on Loona, which has done really well this year, especially when including the yyxy and solo releases, and considering lack of strong sales support in SK. Other takeaways based on the total sales charts:
- WJSN is quietly having an amazing year and passed 100k in sales
- With Blue;s, Mamamoo will also have broken the 100k mark
- fromis_9 also had a great rookie year, with From.9's 30.6k sales lifting them out of nugu status
- The debut of IZ*ONE and growth of WJSN should make 'top five' discussions more interesting
- Dreamcatcher is also growing quickly, with each of their 2018 albums exceeding their total sales for 2017
- Apink and SNSD are still holding strong in their 7th and 11th years, respectively
- Not surprising, but Twice is such a wall that it beats the next three groups combined