But as the IR industry and shareholder environment has matured over the years, comms directors have been tightening their grip on the function, gradually trying to claim it as part of their fiefdom as they have done with other comms-linked disciplines such as CSR or internal communications.
This somewhat natural evolution has, however, received a set back in recent months - believed by many in the City to be a direct result of the Enron collapse, in which the US's seventh largest company was put into administration following allegations of sharp practice and accounting tricks used to dupe investors and protect the share price.
While IR officers have always needed a close affinity to the City, professional financial qualifications have so far been an added bonus. But firms are now beginning to demand that their in-house IR officers have either an accountancy qualification or other financial credentials under their belt.
Many in the industry are raising concerns over this trend and its implications for a practice already caught between finance and communications.
The Investor Relations Society (IRS) believes companies stipulating that IROs should have an accountancy qualification are heading down a dangerous road: 'IROs and PROs have to be up to the job in terms of knowing the rules and regulations, but it doesn't follow that they should be qualified as an accountant,' says IRS director-general Andrew Hawkins. 'It's a knee -jerk reaction because firms are worried about the potential liability of getting their communications with investors wrong.'
Bean counters are not traditionally renowned for their good communications skills, and IR - despite undoubtedly being a financially-oriented profession - is largely a communications role.
As ex-Thomson Financial director of international IR Steffan Williams, now a director at Capital Communication MS&L, says: 'Part of the duty of the IR team is to make sure the firm is fully valued. To do that you need accurate communication and people with an accountancy background may not be strong on that side.'
At pharma giant Shire Pharmaceuticals, the finance department has a great deal of influence over all aspects of communications - both the PR and IR chiefs report to the CFO.
But, according to Shire global head of IR Clea Rosenfeld, companies should seek IROs with a balance of communications and City experience, not just an ability to number crunch.
'Someone with a financial or analyst background may understand the value of good communication, but an accountant - no,' says Rosenfeld. 'Their job is to analyse and project the figures but communications is not their job.'
Kingfisher director of IR Ian Harding is an exception to the rule. A former auditor with PricewaterhouseCoopers and latterly financial controller for the retail group, Harding believes IR is a combination of 75 per cent financial knowledge to 25 per cent comms skills.
He sits within the comms function and works closely with the PR team, but his main concern is knowing the business and having a head for figures: 'It's all very well to communicate the company strategy nicely, but if you can't talk about the figures it's no good.'
IR specialist headhunter Heather McGregor, a Taylor Bennett partner, says the collapse of Enron has caused nervousness, yet adds that some quoted firms already insist on their IR staff having professional qualifications - in accounting or finance.
'Companies have always been demanding about the level of financial knowledge needed in IR,' says McGregor. 'If you do not have a strong financial background, it doesn't matter if you report to the finance or communications director, you won't have the necessary knowledge.'
The IRS is keen to strike a balance - to make sure IR is not handed over to finance while recognising the need for greater professionalism.
This week the IRS announced plans at its annual conference to help develop the country's first professional qualification in IR in a bid to ease the pressure of having a formal accountancy qualification.
Hawkins is hoping this could lead to a Europe-wide standard and a better mix between communications and City experience among practitioners.
The debate appears to be moving on from which senior manager IROs should report to. With close collaboration between PR and IR, it should not matter.
These days the industry is more focused on raising the professionalism of IR. As Harding notes: 'In the past the role of the IR person was someone who organised the CEO's diary - now they're very much in the front line.'
And the industry is beginning to recognise that it must lead the way in creating its own professional qualification.