He also didn't mention COY either, and I'm quite sure Dork32 is capable of posting in this forum.
I do. Maybe we evaluate the cost of bank branch queuing differently.
But it's not like that. It's not online shopping at Site A versus online shopping at Site L. The unit trust-based SA shielding method is the online shopping. You can do it from your sofa. (Well, most people can.) Buying a 6 month T-bill for SA shielding requires queuing at a bank branch. So the comparison is online shopping versus "brick and mortar" shopping. I find online shopping more convenient (less costly), so I assign some cost to the "brick and mortar" option. I also assign some cost to the risk that the SA interest rate will unpeg from its floor (rise above 4.0%) during the latter month(s) of the 6 month T-bill. Then I estimate what COY/EIR would be sufficiently attractive for me to favor T-bill-based shielding over bond unit trust-based shielding, and currently I have set those numbers to be 4.25%/4.33% based on how I feel about the net cost and risk differences. That also happens to be the equivalent of about half a month of SA interest at the floor rate (T-bill relative to unit trust).
How would you bid (COY) if you were bidding in the next 6 month T-bill auction for SA shielding purposes?