UK investment firms do not have to report any transactions through a UK APA.
SteelEye enables financial firms to manage their regulatory obligations through a single platform.
The acquisition will help to further expand Trax's reporting and data services in Europe.
The regulator analysed a sample of 8,000 EU companies between 2006 and 2019.
The association said improving data should be prioritised.
The not-for-profit initiative will make it easier to ensure funds are comparable and clear about costs.
Research fintech Limeglass has doubled its team since an investment by JP Morgan last year.
Regulator says systematic internalisers make a limited contribution to transparency.
Open access was first identified in 2001 as a key element of an integrated EU post-trading landscape.
