Investor's risk in the event of a change in interest rates on bond market

Even if an investor wants to actively manage his portfolio, he should study in detail what the behavior of the bonds is based on their maturity, their yields and in the event of a change in interest rates. An increase in interest rates will lead to a reduction in the prices of all bonds. 
One risk to consider is that the issuance rates of new bonds also change the returns required by investors to buy or sell bonds already issued. Bond prices correspond in the opposite direction to interest rates, in which case an increase in interest rates will result in a fall in the prices of all bonds. Another risk is the decision to choose a bond based on the maturity time, where the longer the time, the more volatility it will have due to the change in interest rates. As well as the percentage change in the price of the bond increases with a decreasing course when the maturity of the bond increases. But even in the case of an equal change the yield at maturity will not be symmetrical in any case. Finally, the investor should calculate the risk in the behavior of interest rates, where the smaller the interest rates of the bond, the greater its volatility in price, as interest rates change.
In summary, the investor should calculate the risks based on the bond maturity maturity parameter and the amount of the issue interest rate, ie the bond interest rates he wishes to add to his portfolio. These two factors are the interest rate risk.

How the development in bond prices and yields are related to investment financing costs and consequently with economic activity

According to the law of supply and demand, bond prices behave similarly to those of other derivatives. That is, as demand increases, bond prices increase and correspondingly, when demand decreases, bond prices decrease, provided that the other factors remain stable. In the event of a change in supply, the increase reduces the price of the bond, while the decrease in supply will increase the price of the bond. 

Price and yield of bonds are characterized by a negative relationship, with each change of one moving the other in reverse. So an investment financing by increasing the bond offer to finance a company, this increase in the bond offer has the effect of reducing their price and increasing the yield of the bonds. A similar behavior can be seen in the case of government securities with the tactic of reducing the bond market, with the ultimate goal of raising interest rates in the economy, known as quantitative easing (QE) with bond prices falling and interest rates (yield) ) to increase. 

In both cases the behavior of the basic economic equilibrium is observed with the decrease of the price to increase the yield of the bond with the corresponding increase of the price to decrease of the yield itself. 

Total assets of "Big Banks" in Europe and US by total asset cap

The total assets of commercial banks in both systems under consideration may differ (€ 37 trillion in Europe and $ 23 trillion in US dollars), but the ratio of the sum of the 20 largest banks in each system to the industry as a whole (ie of Europe and the USA respectively) continues to be close. This can be understood if we look back to the past where the trend of consolidation began to emerge, initially as National Unification which offered opportunities to reduce costs through mergers in the domestic market. Then due to the global economy, with an emphasis on cross-border mergers leading to an even smaller number of banks with large financial institutions offering a variety of retail services from simple deposits and short-term loans to large venture capital fund management.

The shrinking numbers of banks in both systems, with the 20 largest commercial banks in each system accounting for 85% and 82% in the US and Europe. The ultimate goal in mergers is for commercial banks from mergers and acquisitions, so that through range savings the additional services offered reduce the average cost, as well as economies of scale where offering a larger volume of services in an expanded market manages to reduce overall costs. Through merger you achieve the ultimate goal of reducing costs, accessing new markets, offering new services and consolidating large financial institutions by gaining a large share of the domestic and global market.