Bond market
The bond market is the largest area of investment in the world. Whenever a government or a business borrows money they usually do it through the bond market. The fact that there is so much money being traded on the bond market makes it an area that you really need to have money invested. Bonds can be surprisingly confusing so most people tend to shy away from them. However if you know a few of the basics there is no reason not to invest in the bond market.
The bond market is where bonds are traded. A bond is simply a means by which governments and corporations borrow money. They have figured out that rather than taking a loan from a bank they can borrow money at a lower rate if they offer the loan directly to investors. In order to do this the issue bonds. A bond will have a set term and will pay interest over the length of the bond. At the end of that term the initial investment will also be returned. A bond is generally considered to be a safe investment but there are no guarantees. If the company that issued the bond goes bankrupt there is a good chance that you will end up losing money. Government bonds are generally safer but there is still the chance that the government will default on its bonds. This mostly happens with municipal governments who spend more than they can afford.
The simplest way that you can invest in the bond market is to just buy the bond and hold it until it matures. This guarantees that you will get the amount that you originally thought you would. However bonds are frequently traded on the bond market. The price of a bond will fluctuate because of changes in interest rates. If the prime rate goes down then bonds that are issued in the future will have a lower interest rate. Therefore bonds that were issued earlier at higher interest rates will have more value and will go up in price. The opposite happens if interest rates go up. There are a great many people and institutions that make the bulk of their income trading bonds. It is basically a way to profit from changes in the interest rate.
The concept of a bond is fairly simple but it has turned into an enormously complicated area of investment. There are now dozens of different bond products available. Combine this with the fact that bonds are actively traded and it can be confusing to most people. This is why for the average person the best way to invest in the bond market is through a mutual fund. This will allow them to put their money into a fairly safe investment without having to understand all of the complexities of the bond market. The mutual fund manager will buy and sell bonds as appropriate to maximize your returns.