HFC GmbH’s mandate requires integrating shortlisted trading engines into our client’s existing OMS/EMS while maintaining demonstrable best-execution under MiFID II. To those who have acquired fintech platforms where post-merger API harmonisation was mission-critical, what integration sequencing, contractual safeguards or earn-out structures effectively aligned vendor incentives with a swift, non-disruptive cut-over, and what unforeseen frictions merited contingency buffers in your original deal thesis?