This report examines the experiences with a collaborative compliance project – Enhanced Customer Cooperation (ECC) – introduced by the Finnish Tax Administration. The ECC was introduced by the Large Taxpayers’ Unit of the Finnish Tax Administration at the beginning of 2013, and it ran as a pilot until the end of 2015. Since the start of 2016, the ECC has been a part of the permanent operations of the Large Taxpayers’ Unit. Based on the interviews with tax officers, corporations participating in the ECC and tax lawyers and tax consultants, the ECC is bringing about a cultural change in the administrative practices and ways of communicating between tax authorities and taxpayers. In general, the ECC’s objective of increasing cooperation between tax administration and taxpayers has been welcomed. There were, however, some concerns about the impartiality towards taxpayers, efficiency in the use of human resources and the possible retrospective involvement of the Tax Recipients’ Legal Services Unit. In addition, because predictability was described as one of the key aspects of taxation for companies, many questions have been raised regarding whether the ECC can deliver more predictability in taxation practices.