the law in the United Kingdom required that renewal fees be paid on the anniversary of the filing date rather than on the last day of the month. Following amendments made by the Patents Act 2004, The Patents (Amendment) Rules 2005, which came into effect on 1 October 2005, ensured that any period prescribed for payment of a renewal fee does not expire until the end of the month in which the renewal date falls. United States For all issued utility patents stemming from applications filed on or after December 12, 1980, the USPTO requires three renewal payments at 3½, 7½ and 11½ years after the date of grant (the payments can be made no sooner than 6 month prior to the due date). No maintenance fees are due while an application is pending. Several adjustments have been approved by the Congress since: 1980: Public Law 96-517 – Establishes patent renewal (maintenance fees) due at three time periods (stages). 1982: Public Law 97-247 – Establishes the patent small entity discount for all fees set by Congress and the Trademark "fence" (Trademark user fees may be used only on trademark related operations). 1990: Public Law 101-508 – A 69% surcharge is applied to all patent statutory fees. The agency becomes fully-fee funded. 1991: Public Law 102-204 – Establishes yearly adjustments to patent statutory fees based on annual increases to CPI. 2005: Public Law 108-447 – Establishes the current USPTO fee structure, including separate patent filing, search and examination fees and discounts for trademark applicants who file electronically and agree to other terms. 2011: Public Law 112-29 (America Invents Act) – Establishes USPTO's authority to set most patent and trademark fees such that aggregate revenue from the fee schedule recovers aggregate costs. Establishes additional small entity fees and new micro entity fees. Design patents and plant patents are not subject to maintenance fees at all. Maintenance fees may not be paid in advance; the patentee must wait until the payment window opens six months before the due date before paying a maintenance fee. At the end of the half-year window during which a maintenance fee may be paid, a six-month grace period begins during which a patentee may still pay the maintenance fee along with a small surcharge (as of 2016: $160 for a large entity, $80 for a small entity; and $40 for a micro entity) in order to maintain the