FTSE AIM 100 Index

The FTSE AIM 100 Index is a of the top 100 companies on the 's Alternative Investment Market weighted by market capitalisation. It comprises a range of businesses ranging from young, venture capital-backed start-ups to well-established, mature organisations looking to expand.

AIM 100 companies must have their primary listing on the Alternative Investment Market, and are required to meet various eligibility criteria. The index may contain companies that are also included in the FTSE AIM UK 50 Index.

When the London Stock Exchange created AIM, the objective was to offer smaller companies the ability to raise capital on a market with a pragmatic and appropriate approach to financial regulation. Since its launch in 1995, over 2,500 companies have joined AIM − raising more than £34bn in the process, both through initial public offerings (IPOs) and further capital raisings. Many companies have made the transition to the Exchange's Main Market following success on AIM.

The index is reviewed quarterly, and the constituent companies may change based on market capitalisation data as at the end of February, May, August and November. The index is maintained by FTSE Russell, a subsidiary of the London Stock Exchange Group.

...
Wikipedia