The fines were levied by the London Stock Exchange for not complying with its rule 26 which was introduced in February 2007.
These companies paid a total of £95,000.
They did not hit a deadline of 20 August deadline for posting a website containing all financial details, including the annual report and regulatory news service announcements.
The rule was introduced as part of the exchange’s first rule book for nomads, the nominated advisers responsible for bringing companies to AIM.
Another seven companies were given warning notices for less serious breaches.
All 16 companies – none of which have been named – rapidly improved their websites to comply with the rules.
The maximum fine for breaching the rule is £50,000.
Fines for the nine companies ranged between £3,000 and £15,000 for breaches, including material omissions, up to having no website.
The introduction of the rule book was seen as one of the most important changes for Aim since its foundation in 1995.
It was a response to increasing criticism – mainly from the US – about a perceived lack of regulation.
The number of companies listed on AIM rose to more than 1,700 for the first time after Steppingstone Associates was admitted.
The communications sector recruitment specialist, raised £1.1m gross through a placing at 4p a share, capitalising it at £6.4m.
The value of Aim secondary placings slumped even more dramatically than new issues in the second half of last year as the credit crunch bit, according to new research.
A survey of the market found that the value of new AIM issues had risen to a record £3.5bn in the first half of the year but estimated a fall to £2.9bn in the second.