Trade and transaction reporting rules under MiFID and EMIR can easily be confused, even though they have different requirements, different formats and, most importantly, different scopes.
To recap, MiFID trade reporting is a short message to the public, intraday, for the purpose of price discovery; transaction reporting is a long message to the regulator, at the end of the day, for market surveillance purposes. In terms of scope, MiFID II restricts trade reporting to instruments that are traded on an EU trading venue and ESMA will conveniently publish this list. But transaction reporting requirements include additional instruments where the underlying is traded on an EU trading venue. To work out the impact, let's consider equity derivatives as a simple example.
It doesn't matter whether the financial instrument is a CFD or an option, on a single stock or an index. If it has an underlying listed in the EU (one constituent in an index suffices), then it is in scope for transaction reporting. This applies even if a MiFID II firm is a member of a non-EU venue, HKEX for example. That doesn't mean that all Hong Kong based firms have to report to Europe, but it does mean that EU firms need to take a global view because the scope of these new rules can reach further than you might think.