Two years after Wall Street’s love affair with fast-twitch stock options began, Bloomberg’s latest Markets Live Pulse survey suggests the unprecedented boom still has room to run — even as almost half of respondents fear an eventual blowup.

Six years after a famous blowup in the volatility market shattered a lengthy calm in US stocks, the latest Bloomberg Markets Live Pulse survey reveals growing Wall Street concern over a new boom in trades that bet against equity turbulence.

Bearish investors are snapping up bullish options to ensure that their defensively positioned portfolios won’t be left behind if the latest rebound in US stocks proves persistent.