The 2007 annual report of Macquarie Bank runs to 120 compendious pages, its uncompromising inkiness broken only by a few small photos, pie charts and graphs. The text is unsigned, and there is not a single image of anyone at the bank, even its managing director, Allan Moss. Curious: Macquarie Bank used to be known for attractive, even imaginative annual reports. There was one that had peepholes in the pages; another had arty metaphorical images that paralleled aspects of investment banking with other occupations. But Australia's most admired corporation does nothing without a reason. It's almost as though the more successful it becomes, the more it aspires to impersonal, monolithic status.

Then there's that name. Apple Computer recently relaunched itself as Apple, explaining that it had left behind old-fangled ‘computers'. The ‘bank' in Macquarie Bank seems almost as archaic. In the financial world, the organisation is neither fish nor fowl, exhibiting characteristics of investment bank, asset manager, buy-out house, private-equity arranger and hedge fund. Perhaps that is why the custom has become simply to enumerate the assets under its control - a cliché beloved of the news media that nonetheless conveys something about Macquarie's diversity and geographic spread. Airports, antennae, casinos, car parks, turnpikes, tunnels: whether in Canada, Korea, Britain, Belgium, Singapore, Spain, Taiwan or Tanzania, all come alike to Macquarie's sophisticated metrics and financial heft.

You are most likely to find Macquarie under your wheels. It has made its name as a long-term holder of big infrastructure assets, and its chief fame is in toll roads. Interests in a host of them - from the Chicago Skyway to Britain's M6 Tollway; from Highway 407 in southern Ontario to the Indiana Toll Road, the so-called Main Street of the Midwest - repose in the Macquarie Infrastructure Group, the oldest and biggest of the bank's 31 specialist infrastructure funds. But Macquarie is no captive of its past. Of its 10,000 staff, 500 are peripatetic dealmakers in worldwide pursuit of the next asset, the next target, the next income stream.

On 15 May, Macquarie announced a record annual profit of $1.4 billion: a 60% increase on the previous corresponding period. For the first time, too, more than half its income came from offshore, and it would have been higher but for the strength of the Australian dollar. It looked like the crossing of an earnings Rubicon. Allan Moss was anxious to assure Australians that Macquarie would keep its headquarters here, where 6500 of its personnel are based. But it sounded a little like an ambitious son assuring an elderly parent that he wouldn't lose touch. Nor is it surprising that the bank's admirers can scarce forbear to cheer. Macquarie is a success story - perhaps the Australian business success story of the past decade.

Macquarie opened in Sydney in 1969 as Hill Samuel Australia, an outstation of the tweedy UK merchant bank Hill Samuel. Foreign financiers were then swarming all over Sydney, enticed by the chimeric nickel boom. But Hill Samuel Australia was a stayer, cultivating a reputation for diligence, discretion and, above all, excellent connections. Two of its stalwarts, David Clarke, now Macquarie's chairman, and Mark Johnson, now its deputy chairman, joined from the pioneering merchant bank Darling & Co in 1971, where they had trained under the future World Bank president Jim Wolfensohn. They did their first deal for White River Industries, owned by a wealthy family whose scion had been their MBA classmate at Harvard: Nick Greiner.

Hill Samuel Australia was sometimes more entrepreneurial than it received credit for. It was the fearless sole underwriter in the float of Westfield Trust 25 years ago; it pulled together the intricate structure that made possible BHP's landmark acquisition of Utah International; it launched Australia's first cash-management trust, and the first approved deposit fund not to emanate from a life office. The bank's alumni are among the best and brightest of their generation: ACCC chairman Graeme Samuel, his Grant Samuel co-founder Ross Grant, ING Australia chairman Tony Berg, Allco Equity Partners chief executive Peter Yates, Bendigo Bank chairman Rob Johansen, Goldman Sachs JBWere's investment-banking éminence grise Alastair Lucas. The organisation, nonetheless, would probably have gone the way of all merchant-banking flesh had its executives not successfully detached themselves from the parent company and sought a trading-bank licence in 1985. Then, its after-tax profit was just $7 million, and it would have made a tasty morsel for an acquirer - a fate that befell Hill Samuel in the UK, which disappeared into the maw of Lloyds Bank.

What had been an old-fashioned merchant bank came to resemble more a freewheeling Wall Street investment bank, though Macquarie deployed its capital frugally, building businesses in corporate finance, treasury, property and funds management that did not overtax its balance sheet. Mind you, not until Macquarie's recent spurt of infrastructure-fuelled growth has it been other than mediocre as a manager of investment monies. "It [Macquarie's funds-management business] has always been the runt of the litter," observes John Sevior, the head of Australian equities at Perpetual Investments. "They've never grown funds management, especially on the equities side. They were market leaders in cash management. But until infrastructure, they'd had two or three cracks at it and never gotten anywhere."