strange substantial shareholding disclosure

I've just been looking into who owns OST.

There is a very curious recent disclosure from ANZ

ANZ got 6059 shares off an Opes client
ANZ borrowed 18.996 million shares from stock borrowing OTHER than Opes related.
ANZ hold 417,000 shares through trustee arrangements
ANZ is deemed to have an interest in 29m shares held through its investment funds management JV with ING

Total is 5.5% of OST.

Now the second item is the interesting one. Why would ANZ be BORROWING shares in OST ???

Possibility (1) ANZ has borrowed them from a super fund/insto in order to short-sell them. Seems improbable. ANZ is a bank, not in the hedge fund business. Is it ?

Possibility (2) ANZ has borrowed them in a role as a financier providing quasi-margin-lending finance to some bigshot with lots of OST who needs some cash. Just like Opes did, cutting out the middleman.

These two possibilities correspond to Finkelsteisn notion of two separate markets in stock lending.

So WHO has lent 18m OST shares to ANZ ? Thats more than 100m dollars worth of OST shares. The OST CEO ? Is this somehow related to the very odd counter-market trends in OST observed early in the year ?