RE: TSX Buy-ins When the seller does not obtain the shares within the required time frame, the result is known as a "failure to deliver". The transaction generally remains open until the shares are acquired by the seller, or the seller's broker settles the trade.
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The SEC has stated that naked shorting is sometimes falsely asserted as a reason for a share price decline, when, often, "the price decrease is a result of the company's poor financial situation rather than the reasons provided by the insiders or promoters."[4]
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Short seller David Rocker contended that failure to deliver securities "can be done for manipulative purposes to create the impression that the stock is a tight borrow," although he said that this should be seen as a failure to deliver "longs" rather than "shorts."[19]
https://en.wikipedia.org/wiki/Naked_short_selling