CLK wrote:

The A10 has the most kids in the transfer portal.  Most like due to the number of coaching changes in the League.

Tobias Bass on Twitter: "Transfer Portal Numbers by conference: AAC: 61 A-10: 67 ACC: 61 Big 12: 43 Big East: 56 Big Ten: 40 C-USA: 39 Horizon: 47 MWC: 56 MVC: 49 OVC: 56 Pac-12: 62 SEC: 61 WCC: 37 @TheAthleticCBB" / Twitter

Thanks, CLK.
https://twitter.com/EvanMiya/status/1646561384308539409
This is a look at the % of conference players in the portal (data about 2 weeks old, but correlates pretty closely to the above tweet). Evens it out a bit due to the 15 teams in the A10.