An announcement will be made in the next issue of Shounen Jump to state that the upcoming Bleach arc will be its final.
If you follow Bleach you'll know that it is currently on a three week hiatus, returning next week. There's been some speculation as to why, as it was just recently on hiatus, but consensus seems to be around its dwindling ratings.
Bleach's ratings have been falling few a few years, formerly rivaling Naruto for Jump's second most popular series (both behind One Piece). But in the last ~3 years Bleach's ratings sank and stayed low, continually polling in the bottom five series SJ. Kubo Tite took a brief hiatus at the end of last summer and made an attempt to reboot the series, likely to offer a change in the series and boost its ratings, but the Fullbring arc failed to do so.
It seems the current hiatus is to allow planning for the final arc.
I imagine that the series is ending because SJ has canceled it, not because Kubo is choosing to. He stated on Bleach's 10th anniversary that he wanted to continue the series for another 10 years, and it would make sense for him to voluntarily end the series immediately following a reboot.