Hasn't it been explained before that Macquarie is the "clearing house" for odd lot sizes? So if anyone bought, say, 541 shares, the 500 would be 1 board lot given our share price, and the odd number of 41 would come from Macquarie?

I am pretty sure I remember someone explaining this - but I do not recall who said it nor can I find any information if this is true or just complete nonsense.