Bonds are issued by public authorities, credit institutions, companies and supranational institutions in the primary markets. The most common process of issuing bonds is through underwriting. In underwriting, one or more securities firms or banks, forming a syndicate, buy an entire issue of bonds from an issuer and re-sell them to investors. The security firm takes the risk of being unable to sell on the issue to end investors. Primary issuance is arranged by bookrunners who arrange the bond issue, have the direct contact with investors and act as advisors to the bond issuer in terms of timing and price of the bond issue. The bookrunners’ willingness to underwrite must be discussed prior to opening books on a bond issue as there may be limited appetite to do so.
In the case of Government Bonds, these are usually issued by auctions, called a public sale, where both members of the public and banks may bid for bond. Since the coupon is fixed, but the price is not, the percent return is a function both of the price paid as well as the coupon. However, because the cost of issuance for a publicly auctioned bond can be cost prohibitive for a smaller loan, it is also common for smaller bonds to avoid the underwriting and auction process through the use of a private placement bond. In the case of a private placement bond, the bond is held by the lender and does not enter the large bond market
http://en.wikipedia.org/wiki/Bond_%28finance%29
