The benchmark S&P/ASX 200 index on Wednesday closed down 13 points, or 0.2 per cent, at 5737.

A more positive night on Wall St inspired morning gains on the local bourse, but those had evaporated by around midday as investors savaged the likes of insurer IAG and Healthscope, which ended the session down 8 per cent and 15 per cent, respectively, after revealing annual profit figures. The market was similarly unimpressed by Coca-Cola Amatil's earnings release, pushing the stock down 2.6 per cent.

The biggest name reporting on a hectic day of earnings was supermarket owner Woolworths, which reversed early gains to end the session down 0.4 per cent as it reported a dip in net profits thanks to large losses at Big W. AMP was also a drag on the bourse, dropping 3.1 per cent as it traded ex-dividend.

News then emerged around mid-afternoon that Trump at a rally said he may end the North American Free Trade Agreement. He then threatened to shut down the US government if he was unable to get funds to build a wall along the Mexican border. Those utterances sent the yen climbing, S&P 500 index futures slipping, and may have served to cruel a late attempt by the ASX to recover the day's losses.

"[Trump's] comments on the Nafta negotiations once again brings the general direction toward obstructing free trade and raises concerns over its impact on global trade," Daiwa Securities senior strategist Hideyuki Ishiguro said.

It wasn't all bad news for shareholders. The market reacted enthusiastically to earnings releases from a2 Milk, which added 6.9 per cent, Star Entertainment, which climbed 5.1 per cent, and Qube Holdings, which pushed up 3.4 per cent. Those gains helped limit the day's losses on the bourse.

BHP added 0.2 per cent as investors and analysts continued to parse Tuesday's profits report. The Big Australian also reshuffled its board, announcing that former Origin Boss Grant King would not be seeking reelection as a director.

There was more bad news for CBA shareholders after plaintiff law firm Maurice Blackburn said it would look into a potential class action on behalf of said shareholders over the bank's disclosure of more than 53,000 alleged breaches of anti-money laundering laws. CBA ended the session down 0.6 per cent.

Stock Watch

Sydney Airport

Sydney Airport lifted for a second session in Wednesday, adding 1.7 per cent to $7.20 as a trio of broking houses upgraded the stock following the previous day's well-received profits release. "While operationally a bit weaker than expected, the underlying trends remain positive, particularly [for] international traffic and retail," RBC Capital Markets analysts wrote as they lifted their cash flow and dividend estimates for the company - a key consideration for income hungry investors. The RBC analysts upgraded their rating to a "sector perform", while UBS analysts upped their call on the stock a "buy" and Shaw & Partners to "positive". "Even assuming international traffic growth moderates we see a period of stable [around] 9 per cent annual growth in [cash flow per security] over the next three years," the UBS analysts wrote.

Movers

Iron ore

Iron ore futures in China retreated 3.6 per cent on Wednesday as a sell-off in steel drags down prices of the steelmaking raw material, cutting short a rally that lifted iron ore to five-month highs this week. But traders said the losses in steel prices may be fleeting as underlying demand in China, the world's top producer, remains strong and supply tight amid Beijing's reforms to curb overcapacity. "Fundamentally, the physical steel market still looks healthy with supply-side reforms restricting supply and demand remains firm," said a Shanghai-based trader.

Volatility rising?

The 22 per cent plunge in BlueScope Steel on Monday and a 15 per cent plunge in Healthscope on Wednesday added weight to the idea that earnings seasons are becoming more volatile. But JP Morgan Aussie equity strategist Jason Steed is not totally convinced. "Over the past seven years, volatility in February has only been above the annual average 38 per cent of the time and for August it's just half of the time," Mr Steed said. A particular challenge "is unpicking geopolitical currents from stock-specific events," he added, noting there is a 92 per cent correlation between volatility on the ASX and Wall Street.

Typhoon Hato

There was no trading on the Hong Kong stock exchange on Wednesday as a strong typhoon lashed the financial centre and other parts of southern China. Trading was suspended in the securities market, including Stock Connect trading with mainland Chinese markets, and the derivatives market. The halt was in accordance with the exchange's trading rules for bad weather. The city's observatory hoisted storm signal No. 10 - the highest on its scale - for only the fourth time since the early 1980s. Hundreds of flights and other transport services were cancelled, and schools and most businesses in the city were expected to be closed for the better part of the day.

Foreign power powers on

The New Zealand dollar slipped a touch on Wednesday after the New Zealand government trimmed its economic growth and budget surplus forecasts a month before the general election. Surpluses from 2019 through 2021 will be slightly lower than previously forecast, according to a pre-election fiscal update. Economic growth will accelerate to 3.5 percent in the year to June 2018, a touch less than estimated in the budget, and will slow more than previously expected in later years. The fiscal update still paints a picture of a robust economy as the ruling center-right National Party seeks a rare fourth term in office at the September 23 election.