Hong Kong’s stock market has moved into line with global peers, with the exchange operator’s launch yesterday of a circuit breaker to prevent extreme volatility.

香港股市昨日启用市场波动调节机制以防止极端波动，此举使其与全球市场接轨。

The stock-specific approach differs from an attempt by China this year to tame extreme price moves, which regulators had to scrap after only four days when it resulted in the shutdown of the entire stock market within the first half hour of trading on January 7.

这种针对个股的机制与中国内地今年初旨在抑制极端价格变动的尝试不同；中国的熔断机制在1月7日导致整个股市在开盘半小时后就停摆，监管机构在仅4天后不得不放弃这一机制。

The volatility control mechanism has been introduced in an effort to prevent “extreme price volatility arising from major trading errors and other unusual incidents”, Hong Kong Exchanges & Clearing said.

香港交易及结算所有限公司（Hong Kong Exchanges and Clearing，简称：港交所）表示，市场波动调节机制(VCM)旨在防止“因重大交易错误或其他异常事件而引发的极端价格波动”。

The VCM was rolled out yesterday morning and “the market has been operating smoothly”, the bourse operator said.

这家股市运营商表示，市场波动调节机制在昨日上午推出，市场运转顺畅。

The Hang Seng closed 0.3 per cent higher.

恒生指数(Hang Seng index)收盘涨0.3%。

The VCM applies to specific stocks rather than the market as a whole. It will cover the 50 members of the Hang Seng benchmark and H shares — the 81 constituents of the HSCEI — as well as related index futures contracts.

市场波动调节机制针对特定的个股，而不是整体市场。它将适用于81只恒生指数及恒生国企指数(HSCEI)的成分股——以及相关的指数期货合约。

The launch of the circuit breaker brings Hong Kong into line with other big markets around the world, and in the region including Japan, South Korea and Singapore, which all have similar mechanisms in place.

此次推出的断路器机制使香港与世界各地，包括亚洲的其他大型股市（如日本、韩国和新加坡）接轨，它们都已实施了类似机制。

It follows Hong Kong’s reintroduction, this month, of a closing auction — standard for other big global bour-ses as a way of smoothing end-of-day volatility and as a tool for fund managers who must execute at closing prices.

在此之前，香港在本月重启收市竞价机制，这是全球其他大型股市的标准做法，目的是平抑尾市波动，并作为必须以收市价执行交易的基金管理公司的工具。

Since scrapping a previous incarnation in 2009 that instead caused large price swings in stocks including HSBC, Hong Kong had been the world’s only developed market without a closing auction.

旧版收市竞价机制因为在2009年加大了汇丰(HSBC)等股票的波动而被取消。之后香港一直是世界上唯一没有收市竞价机制的发达市场。

The VCM is not expected to be triggered often, nor is it the sort of market-wide circuit breaker that shut down China’s share market in January.

预计市场波动调节机制不会经常被触发，而且它不是那种在今年1月导致中国内地股市提早关闭的针对整个市场的熔断机制。

Roger Lee, head of markets at HKEx, said: “Given that the VCM is designed to safeguard the market from extreme price volatility arising from major trading incidents, market participants should not expect it to take effect very often and should continue to exercise due care . . . in their trading.”

港交所市场主管李国强(Roger Lee)表示：“市调机制主要是为了避免市场因为重大交易事故而出现极端价格波动，市场参与者无需担心市调机制会频繁触发；我们提醒市场参与者应继续注意投资风险，谨慎投资。”

Steven Sun, head of China equity strategy at HSBC, said China’s failed experiment in January had left such a “bad memory . . . [that] Hong Kong doesn’t want the VCM to be viewed as a trading suspension that’s like the circuit breaker in China”.

汇丰中国股票策略主管孙瑜(Steven Sun)表示，中国在1月份失败的实验留下了如此“糟糕的记忆……香港不希望市场波动调节机制被视为中国的熔断机制那样的交易暂停”。

A Hong Kong-listed stock affected by the VCM will enter a five-minute cooling-off period if its price is more than 10 per cent away from its last traded price five minutes ago. Rather than being halted, the stock will be restricted to trading within a 10 per cent band either side of a reference price during the cooling-off period.

市场波动调节机制覆盖的一只香港上市股票，如果股价相比5分钟之前的最后一次交易价有超过10%的差异，那么它将进入5分钟的冷静期。该股的交易将不被禁止，而是在冷静期被限定在一个参考价上下10%的区间内买卖。

HKEx has backtested the VCM using historical data for the past nine years and said there was “no trigger for most years” — even in 2015, when China’s market surged in May and the Hong Kong market experienced record turnover, and in January of this year when global markets were gripped by levels of volatility last experienced during the financial crisis.

港交所使用过去9年的历史数据对市场波动调节机制进行了回溯测试，表示“多数年份没有触发事件”，即使在2015年也不例外，当时中国内地股市在5月份行情大涨，香港股市出现创纪录的成交额，而在今年1月全球股市出现金融危机过后未见的波动水平时也是如此。

There would have been no triggers in the derivatives market over the nine-year period, the HKEx said.

港交所表示，衍生品市场在整个9年期间未曾发生触发事件。