In broad-based gains, the benchmark S&P/ASX 200 closed up 0.7 per cent, to 5912 points, having traded as high as 5923 points shortly after the open, while the broader All Ordinaries Index rose 0.6 per cent to 5937.

The market is eyeing the 6000 level on the benchmark index - a threshold that it has repeatedly tried and failed to overcome. On Tuesday night, the tech-heavy US Nasdaq index broke through 6000 points for the first time. On Wednesday night US President Donald Trump is expected to outline his tax plans, which could give Australian equities another boost.

Katana Asset Management portfolio manager Romano Sala Tenna said the market was one solid day's trading away from the level. But it would take a robust plan to get there.

"There's a level of optimism built into the indices," he said. "Now things need to go right to maintain these levels. We need to see some follow-through on the Trump tax trade.

"Our view is there's a higher probability of it succeeding than otherwise, but there's no guarantee."

Financial stocks were responsible for most of Wednesday's solid showing. ANZ added 1.3 per cent, CBA 1 per cent, NAB 0.7 per cent and Westpac 0.6 per cent. Macquarie Bank jumped 2.6 per cent.

Heavyweight mining stocks did their bit, with the exception of the gold miners who suffered as investors dumped safe havens for more cyclical asset classes. Regis Resources, Newcrest Mining, Northern Star Resources were down 6.5 per cent, 4.9 per cent and 7 per cent, respectively.

Rio Tinto rose 1.1 per cent, Fortescue Metals pushed up 1.3 per cent, while BHP Billiton added 0.6 per cent.

BHP's strong showing came despite it being cut to a sell at Goldman Sachs, and it lowering its production guidance across several commodities in its third-quarter update, said Mr Sala Tenna.

"The market was well-guided and well-versed in advance of the result, which is why they're up," he said. Meanwhile, another miner, Independence Group, was punished 3.4 per cent after a disappointing quarterly result. "They did miss where the market thought they'd be at," said Mr Sala Tenna.

Bluechips posted solid gains. CSL was up 1.2 per cent, Telstra rose 0.7 per cent, and Woolworths and Wesfarmers rose 1.2 per cent and 0.4 per cent respectively.

The a2 Milk Company rose 7.7 per cent to $3.20, an all-time high and the day's best performer in the top 200, after the company lifted its full-year revenue guidance on strong sales.

Stock watch: Ardent Leisure

Ardent Leisure shares bumped up 1.5 per cent on Wednesday after chief executive Deborah Thomas was replaced by former Nine Entertainment chief operating officer Simon Kelly. The move comes a month after corporate raiders Gary Weiss and David Baffsky built up a stake in the troubled theme park and arcade operator. Mr Kelly will become chief executive officer and managing director on July 1, Ardent said this morning. Ms Thomas will take the roles of chief customer officer for the group and chief operating officer for its Australasian business. Under Ms Thomas's watch the company suffered a fatal accident at its Queensland theme park Dreamworld in October and reported a weaker-than-expected performance at its US Main Event Entertainment business in February.

Inflation

Headline inflation is back within the RBA's target band for the first time in two years, at 2.1 per cent over the year to March, according to ABS data. That's up from 1.5 per cent in the December quarter numbers, but below the 2.3 per cent consensus forecast. The consumer price index (CPI) added 0.5 per cent over the March quarter, below the 0.6 per cent expected by economists. Core inflation as measured by the trimmed mean, which strips out volatile items such as food and energy, was 0.5 per cent over the quarter. The Aussie dollar slipped.

US trade risks

Investors are looking again at US trade policy after the Trump administration slapped tariffs of up to 24 per cent on imported softwood lumber from Canada. The Canadian dollar dropped 0.5 per cent against the greenback on the news, but then held steady throughout Wednesday. Trump's trade policies have made Australian investors nervous, especially after Washington instigated a probe into Chinese steel imports on Monday. The probe could result in efforts by the United States to curb imports from major trade partners like China and Australia.

BHP update

BHP Billiton will sell some of its US shale acreage, an admission that comes barely two weeks after an activist fund publicly urged it to demerge its US petroleum assets.The prospect of selling the gas-rich Fayetteville shale in Arkansas was revealed by BHP in its March quarter production report, which also revealed that copper production targets had been cut for the second time this year and coking coal targets had also been cut. BHP has in recent weeks tried to rebuff an alternate strategy manifesto published by activist investor Elliott Associates.

Wall Street

A wave of optimism has swept through US equities this week as investors await the reveal of Trump's tax plan and positive earnings results push the markets higher. The Nasdaq Composite hit a record high on Tuesday, while the Dow and S&P 500 are brushing against recent peaks as strong earnings underscored the health of corporate America. Overall profits of S&P 500 companies are estimated to have risen 11.4 percent in the first quarter, the most since 2011, according to Thomson Reuters.