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.

With the notional value of zero-days-to-expiration contracts tied to the S&P 500 hitting roughly $862 billion in April, almost 90% of 300 MLIV Pulse respondents said they expect the growth to continue. The twist? They’re about evenly split on whether it will grow steadily or end in calamity.