The second period is characterized by efforts to reform the DTA regime by
preventing under-taxation, which had become a pressing problem fromthe 1960s onwards. Governments tried indirect reform by devising unilateral
anti-avoidance rules and actively diffusing them to other OECD countries.
Another indirect measure was the modernization of the ALS in the 1980s
and 1990s. From the mid-1990s on, with the problem having come to
full blossom, reform efforts became more determined as evidenced by
the OECD project on harmful tax practices. Ultimately, however, these
attempted reforms have led only to incremental change, leaving the basic
institutional setup unchanged.