(Bloomberg) -- Bets against the world’s largest exchange-traded fund have plunged back to pre-pandemic levels seen about a year ago, before the onset of the fastest stock bear market in history.

Fueled by vaccine hopes and reflationary signals, short interest in the $334 billion SPDR S&P 500 ETF Trust (ticker SPY) now sits at just 2% of shares outstanding, according to IHS Markit Ltd. data.

Barring melt-ups in 2017 and early 2020, these levels have rarely been seen over the past decade.

Falling short interest generally indicates growing faith in a stock rally because it suggests holders are unwilling to lend out the shares they own or that demand to borrow and bet against them has dropped. Still, as speculative mania engulfs Wall Street from Tesla Inc. and Bitcoin to call options, vanishing shorts may be seen as yet-another sign of market complacency.

“First-quarter euphoria has taken hold,” said Peter Chatwell, head of multi-asset strategy at Mizuho. “The second quarter’s likely massive growth rebound is viewed as sufficient to protect equity markets against downside in the coming months.”

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