Modern business leaders know it is important to be able to work fast, adapt to change, and build on existing solutions. This is especially true of digital business, where the high rate of change creates a continuous stream of new problems and new opportunities. Many have called for business leaders to adopt more ‘agile’ structures and processes that embrace change, transparency, and employee empowerment. Now a new complementary approach called ‘inner source’ is emerging to help address this. Inner source does not only embrace speed and change; it also lays out techniques for globally distributed agile teams to systematically store and reuse solutions in a shared, organization-wide repository. This paper explores this new management concept – where it came from, what it means – and illustrates its value in large organizations. Building on a number of illustrative cases, we explain how certain business leaders have brought the principles and practices of inner source to their respective organizations.