"There was a lot of optimism about a potential V-shaped recovery and we've had some cold water in the face of those expectations."
The shock to investor sentiment broke an eight-day run higher in Australia, where the S&P/ASX 200 Index dropped 2.9 per cent in its biggest fall since April. Hong Kong's Hang Seng fell 1 per cent and Japan's Topix was down 1.9 per cent.
Air New Zealand led the local market lower, plunging 10.8 per cent to $1.66. McCarthy said the vanishing optimism prompted speculative investors who had piled into the stock to exit just as quickly.
Kathmandu Holdings fell 9.2 per cent to $1.19, and is now down 2.5 per cent this week despite strong gains on Monday.
Westpac Banking Corp dropped 7.5 per cent to $19.80 and Australia & New Zealand Banking Group declined 5.6 per cent to $20.92.
McCarthy said a steady low-interest rate environment made it harder for banks to increase margins and were always vulnerable to a downturn.
"Banks are leveraged to the economic cycle, when we see growth concerns kicking in they often feel the weight of it," he said.
Gentrack Group fell 7.2 per cent to $1.67. The stock is tipped to be relegated out of the NZX 50 in the index's rebalancing tomorrow. Napier Port, which is expected to replace Gentrack, fell 2.2 per cent to $3.54.
Companies tied to the economic recovery were also under pressure.
SkyCity Entertainment Group slipped 4.6 per cent to $2.91, Sky Network Television dropped 3.2 per cent to 18 cents and Auckland International Airport fell 2.3 per cent to $6.75.
Tourism Holdings dropped 2.1 per cent to $2.34. The rental campervan operator said it was seeing domestic demand gain momentum in New Zealand, Australia, and the United States.
Fisher & Paykel Healthcare posted the day's biggest gain, rising 1.9 per cent to $28.85. The kiwi dollar dropped on the gloomier economic outlook today, which is a boon for F&P which generates half of its revenue in US dollars.
Meridian Energy rose 0.8 per cent to $4.89, while Contact Energy fell 1.1 per cent to $6.30.
Outside the benchmark index, medicinal cannabis research firm Cannasouth rose 2 per cent to 52 cents after it said it was considering a move into animal products as part of its diversification into value-added markets for its cannabinoid products.