When Netia decided to buy two Polish telcos at the same time, they engaged SLI to take responsibility for designing and facilitating the ‘below-the-waterline’ cultural integration of the five different business entities involved in the deal. Working in parallel with The Boston Consulting Group, who carried out the ‘above-the-waterline’ business integration pieces, SLI developed an internal cross-functional and cross-company team of front line employees who we trained to carry out much of the process. Without this internal Organization Effectiveness (OE) Team, the merger of the workforces could not have happened as smoothly and effectively as it did. A side benefit is that this OE Team represented a new capability not present in the company before the merger. This merger was regarded by the client and by the Boston Consulting Group as one of the most successful mergers they have experienced- both Above and Below the Waterline. Our work with the OE Team was presented as a case-study of how to do mergers the right way at the inaugural ODN Europe Conference in London, attended by the best in field from the US and Europe.