Ann: Becoming a substantial holder, page-22

They are not shorting the stock themselves. The scenario discussed above was whether they might lend shares to short sellers.

To me I can't see any reason why they would "trash the stock" as you say. There is simply no benefit in it to them.

Lets say hypothetically, they lend 20% of their holding (or 1% of A2M's overall shares) and that goes on to be shorted.

1) If the SP decreases, the shorters profit whereas Vanguard would see a decrease in the value of the other 80% of their holding. This would far outweigh what they make in lending fees/interest etc

2) if the SP increases, Vanguard profits on their main holding + still rakes in the interest /borrowing fees.

Explain to me why on earth they would prefer outcome 1 over outcome 2 - it would make no sense.