Gilts
A gilt is a UK Government liability in sterling, issued by HM Treasury and listed on the London Stock Exchange. The term “gilt” or “gilt-edged security” is a reference to the primary characteristic of gilts as an investment: their security. This is a reflection of the fact that the British Government has never failed to make interest or principal payments on gilts as they fall due.
Conventional Gilts
Conventional gilts are the simplest form of government bond and constitute the largest share of liabilities in the Government's portfolio. A conventional gilt is a liability of the Government which guarantees to pay the holder of the gilt a fixed cash payment (coupon) every six months until the maturity date, at which point the holder receives the final coupon payment and the return of the principal. The prices of conventional gilts are quoted in terms of £100 nominal. However, they can be traded in units as small as a penny.
A conventional gilt is denoted by its coupon rate and maturity (e.g. 4% Treasury Gilt 2016). The coupon rate usually reflects the market interest rate at the time of the first issue of the gilt. Consequently there is a wide range of coupon rates available in the market at any one time, reflecting how rates of borrowing have fluctuated in the past. The coupon indicates the cash payment per £100 nominal that the holder will receive per year. This payment is made in two equal semi-annual payments on fixed dates six months apart (these payments are rolled forward to the next business day if they fall on a non-business day). For example, an investor who holds £1,000 nominal of 4% Treasury Gilt 2016 will receive two coupon payments of £20 each on 7 March and 7 September.
Index Linked Gilts
Index-linked gilts (IGs) form the largest part of the gilt portfolio after conventional gilts. The UK was one of the earliest developed economies to issue index-linked bonds for institutional investors, with the first issue being in 1981. As with conventional gilts the coupon on an index-linked gilt reflects borrowing rates available at the time of first issue. However, as index-linked coupons reflect the real borrowing rate for the Government rather than the nominal borrowing rate there is a much smaller variation in real yields over time.
Index-linked gilts differ from conventional gilts in that the semi-annual coupon payments and the principal are adjusted in line with the UK Retail Prices Index (RPI). This means that both the coupons and the principal paid on redemption of these gilts are adjusted to take account of accrued inflation since the gilt was first issued. For index-linked gilts whose first issue date is before July 2002, the Bank of England performs the function of calculating and publishing the uplifted coupons on each index-linked gilt following the release of the RPI figure which is relevant to it, while for index-linked gilts first issued from July 2002 onwards the DMO (Debt Management Office) performs this function. | 
