Utilisation

Utilisation measures how much of the available borrow has already been taken. The numerator is shares currently on loan; the denominator is the lendable pool — the shares held by institutions participating in securities lending programmes and made available to borrow. It is a supply gauge, and it behaves very differently from short interest, which measures positions rather than availability.

The two can diverge sharply. A stock with modest short interest can run high utilisation if only a small fraction of its register lends, which is common where founders, a parent company or retail holders dominate the share list. Conversely a widely held large-cap can carry a large short position at low utilisation because the lendable pool is enormous. Utilisation is the better read on how close a stock is to running out of borrow.

As it climbs, the economics change. Lenders price the remaining supply higher, so borrow fees rise and the stock drifts toward hard-to-borrow status. Above roughly 90% there is almost no headroom: new shorts cannot be established, existing borrows cannot easily be replaced, and any recall forces a genuine buy-in rather than a switch to another lender. That is the supply-side setup behind most squeezes.

Recall risk rises with it. Lenders pull stock back for dividend record dates, annual general meeting votes and corporate actions, and when utilisation is already high the borrower has nowhere to go. The forced covering that follows is not a change of view — it is a supply failure.

Australian utilisation data is not public. Loan balances and lendable supply sit with prime brokers, agent lenders and commercial data vendors, unlike the net short positions ASIC publishes with a four trading day delay. Working from the public data alone, the closest available proxies are a high short position relative to shares on issue combined with a small free float and thin average daily volume.

One further caveat: the lendable pool is not fixed. It expands when a new institution joins a lending programme or an index fund grows its holding, and it contracts when a lender sells, withdraws or recalls stock to vote. Utilisation can therefore jump without a single new short being opened, simply because supply has shrunk beneath the positions already in place.