A proposal by the Netherlands to renegotiate its tax treaties with 23 least-developed countries marks a turning point for a country that has until now deflected accusations that it is a key player in tax avoidance by multinational corporations...The Dutch move stems from a government-commissioned report over the summer which, for the first time, agreed with tax-justice groups that developing countries miss out on substantial tax revenues because of their treaties with the Netherlands...The Dutch propose to insert new anti-fraud provisions in the tax treaties...In a second move, the Dutch will pass on information to tax inspectors in least-developed countries when multinationals request a so-called “tax ruling” in the Netherlands...[T]he Dutch will crack down on letterbox companies by forcing even companies that have not asked for tax rulings to meet the country’s “substance demands”...Advocacy groups in the Netherlands have cautiously applauded the Dutch move, but said the new measures were modest.