I've just had a good look around the WMCA website and read one of their investment reports.
The lending they do looks like infrastructure, housing, green projects, brownfield development, etc. etc.
On the face of it, it looks well governed, very low risk, and turns a profit. I can't see them loaning just to keep Wasps afloat, and they don't loan without security.
It has to be related to the stadium, I'd think, maybe so that Wasps can get refinancing over the line.
To me though, especially given how late in the day it is on the bonds, it looks like a real 'Hail Mary'. If private investors won't touch it, I'd be surprised if Wasps can convince the WMCA to invest. You never know though....