'Stay,' the second-last track of 'BE' album is a Jungkook, RM and Jin subunit song. Jungkook composed and wrote this song originally for his mixtape, yet after listening how good it was, BTS members suggested for it to be included in 'BE' album.

'Stay' debuted at #22 on Billboard Hot 100, it is the highest-charting BTS subunit song on the chart history. 

'Stay' also debuted at #3 on Billboard Digital Song Sales with 58,000 copies sold in the U.S. for the first tracking week. 

Fun fact: 'Telepathy,' which Jungkook also participated in singing, composing and writing debuted at #4 on Digital Song Sales chart, while 'My Time,' Jungkook's solo song which he is also credited as songwriter previously debuted at #2. This results in Singer-Songwriter and Composer Jungkook having three (3) Top5 entries on Billboard Digital Song Sales, which is a very remarkable feat.

'Stay' had charted at #1 on U.S. iTunes multiple times within the first tracking week after 'BE' album release. The song also previously charted at #1 on "Amazon Best-seller Song of 2020 (So Far)." 

Now, 'Stay' is crowned #1 Best-seller Song for the whole of 2020 on Amazon. It is the first K-pop song in history to top Amazon Best-seller Song Year End Chart. Jungkook's solo songs 'My Time' and 'Euphoria' also charted at #5 and #19 respectively.

See the full list of Best-seller Songs of 2020 on Amazon here.

Since its release, 'Stay' had received many praises from fans, media and music industry professionals. Founder of Headline Planet, Brian Cantor posted about 'Stay' on his Twitter account twice, basically saying the song would be a huge hit and appeal to everyone:

American news website, Vox reviewed 'Stay,' stating that the song was exactly their jam. They described it as a multi-layered song that started out with a specific flavor of early-90s pop before opening up into a breezy EDM beat. They added, "You’re lucky I even stopped looping ‘Stay’ to listen to the rest of this album."