ML-Implode News - Stock-Market Tumult Exposes Flaws in Modern Markets

Many traders reported difficulty buying and selling exchange-traded funds, a popular investment in which baskets of stocks and other assets are packaged to facilitate easy trading. Dozens of ETFs traded at sharp discounts to their net asset value--or their components' worth--leading to outsize losses for investors who entered sell orders at the depth of the panic.
Products built to provide insurance for investors came up short. As a result of trading halts in futures tied to the S&P 500 index, it was difficult for investors to get consistent prices on contracts linked to them that offer insurance against S&P 500 declines.

Elsewhere, the value of the most widely tracked Wall Street gauge of investor anxiety, the CBOE Volatility Index, or VIX, wasn't published until almost 10 a.m. Monday, half an hour after stock trading began and after the Dow Jones Industrial Average had already posted its largest-ever intraday point decline. That made it difficult for investors to easily gauge the fear in the market.
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Circuit breakers, which are designed to pause trading in single stocks and ETFs during big moves, were triggered nearly 1,300 times Monday. The circuit breakers were added to make markets more orderly after the May 2010 "flash crash," when the Dow Jones Industrial Average dropped nearly 1,000 points before quickly recovering.

But Monday, they sometimes exacerbated problems by preventing prices from returning to normal levels quickly, according to traders, investors and market observers.

For example, the $2.5 billion Vanguard Consumer Staples Index ETF and the $5.8 billion Vanguard Health Care Index ETF both plunged 32% within the opening minutes of trading. The Vanguard Consumer Staples ETF was halted six times over the course of 37 minutes early in the day, according to trading records. The health-care ETF was halted eight times Monday.

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Stock-Market Tumult Exposes Flaws in Modern Markets