Secret company records in Guernsey, Jersey and the Isle of Man will become publicly available, the islands said.
The beneficial ownership registers, which show the ultimate owner of a company, are currently only accessible by local authorities in the UK's Crown Dependencies.
The new plans would see the records made available to the EU, businesses, and the general public by 2023.
The islands have faced huge pressure from MPs to make the change.
In the UK, the names of any person who owns more than 25% of a registered company are publicly available.
Guernsey's Chief Minister Gavin St Pier said the move was bringing the islands into line with "regional standards" of financial transparency, and that he did not expect that it would discourage businesses from operating there.
While only the local authorities have direct access to the registers in the Crown Dependencies, foreign governments are handed information on request.
What are the plans?
- 2021: The dependencies plan to merge their registers with their EU equivalents
- 2022: Businesses will be given access in order to do their "due diligence"
- 2023: The governments of Guernsey, Jersey and the Isle of Man will bring legislation before their parliaments to make their registers publicly available
Tony Mancini, president of the Guernsey International Business Association, said confidentiality was the "bedrock" of Guernsey's financial model and to "unilaterally" discard it could be economically damaging.
He argued Guernsey's register is "superior" to the UK equivalent because the information is verified by registered trust companies.
John Shenton, a director at the Jersey branch of Grant Thornton, said the move would unnecessarily risk individuals' private information being exposed to "tabloid sensationalism", given it is available to the authorities for "legitimate reasons" already.
In March 2019 a cross party group of MPs, led by Labour's Dame Margaret Hodge and Andrew Mitchell from the Conservatives, attempted to force the Crown Dependencies to make their registers public.
Despite more than 40 MPs signing their proposals, their efforts were unsuccessful, and the legislation was limited to Overseas Territories.
Dame Margaret said she welcomed the proposed change, but expressed scepticism about how "transparent" the final register would be until further clarifications were made by the islands.
"Their action plan is awash with get out clauses, and we still do not know what the register will ultimately look like", she added.