In the US, a rash of disputes between public universities and host cities have developed in regard to the cost and benefits of the town–gown connection. Universities boast that their existence is the backbone of the town economy, while the towns counter with claims that the institution is "robbing" them of tax revenue; but as universities expand their campuses, more land property is removed from local tax rolls. Attempts are being pursued to redefine the basic financial terms and conditions upon which the relationship is based. As tax-exempt institutions, universities have had no legal obligation to contribute to the coffers of city government, but some do make payments in lieu of taxes based on negotiated agreements (as is the case in Boston).