When merging data between platforms, we do everything we can to preserve your data. In order to ensure we don't merge incorrect contact or organisations, any contacts or organisations that we are not 100% sure are the same will not be merged, to ensure your contact data remains fully correct. For contacts, matching is done via email 1, and for organisations, matching is done via organisation name. This may result in duplicates across both Pipedrive and Bexio. Should this be the case, you can merge duplicates with Pipedrive's merge feature, which you can find out more about here