ASX boss Elmer Funke Kupper warned the recent rally in the sharemarket was "more fragile" than it appeared as Australian shares suffered their single biggest fall in nine months.
The benchmark S&P/ASX 200 Index slumped 2.3 per cent, crashing back below the critical 5000-point barrier, after being weighed down by a heavy sell down on Wall Street on worries the US could stop or cut its monetary stimulus program.
The share slide, which sliced $35 billion from the market, coincided with one of the busiest days on the Australian corporate calendar as some of the nations biggest companies, including Qantas, Origin and AMP, delivered a mixed bag of profits.
A reversal in the market's fortunes brings to an end one of the longest winning streaks on the S&P/ASX 200 Index in more than a decade and more than $75 billion has been added to the value of the nation's 200 biggest companies since the start of 2013.
On Thursday the S&P/ASX 200 Index closed at 4980.1 points, with some brokers labelling the fall a modest correction.
"This is probably a healthy break for the market after a strong run," said Mike Kendall, an executive director with JBWere.
"Everyone knows that things just won't go up in a straight line," he said.
Speaking at the operator's first-half results, Mr Funke Kupper said equities markets were lagging the apparent improvement in sentiment and confidence.
"While indices around the world are up significantly . . . volumes continue to be at cyclical lows," he said.
"That also tells us that perhaps the significant rally in the indices is a little bit more fragile than the words 'bull market' suggest.
"We're looking for higher volumes for that to be a more cemented improvement in confidence."
The global chief investment strategist for US funds giant Blackrock, Russ Koesterich, noted Australian equities were trading at nearly twice their book value - a premium to many markets.
Fairfax Media boss Greg Hywood said consumer confidence remained tenuous, despite the recent sharemarket rally.
Delivering the media company's jump in net profit, he noted there was "significant volatility in the market".
Elsewhere, mineral sands miner Iluka cautioned it would axe 200 jobs after delivering a 33 per cent slide in full year profit. While Origin Energy's December-half net profit slumped to $524 million from $794 million, hit by what it termed "challenging operating conditions".
Meanwhile, the recent share rally was yet to translate to a lift in activity in the equity market, with low trading volumes pushing first-half revenues for the Australian Stock Exchange down.
The ASX reported a net profit of $171.1 million for the six months to December, a fall of 2.5 per cent from the previous corresponding period, as revenues fell 3.3 per cent.
Underlying net profit was $171.1 million, down 5.3 per cent. The stock exchange operator declared a fully franked interim dividend of 87.9¢ per share.
"The declining revenue . . . has been fully driven by the continued weakness in the cash equities market," Mr Funke Kupper told a media briefing on Thursday.
ASX shares closed down 3.4 per cent to $35.76 on Thursday.
JPMorgan equity analyst Ismar Tuzovic said ASX's results were "quite vanilla" and in line with expectations.
Mr Funke Kupper said ASX's capital expenditure for the first half of the 2013 financial year was $15.4 million, but he expected the full-year total to lift to $40 million through a "significant investment in new products and services", including an over-the-counter derivatives clearing service for Australia.