US companies hold more than half of the world market share for military equipment, according to a recent study by the Stockholm International Peace Research Institute, SIPRI.

The US company Lockheed Martin remains the undisputed leader among the world's 100 largest defense companies — no other company in the industry made a larger profit in 2017. With sales amounting to $44 billion (€27.8 billion), Lockheed Martin leads the SIPRI ranking by a wide margin.

Germany's largest defense group, Düsseldorf-based Rheinmetall AG, doesn't even account for a 10th of this sum. With sales of $3.4 billion, Rheinmetall ranks 25th.

Read more: German arms exports — What you need to know

Big buyer: Washington

The success of front-runner Lockheed Martin is based primarily on the large equipment requirements of the US armed forces, for which the group manufactures various weapon systems. These include the F-35 Lightning combat aircraft and the C-130 Hercules transport aircraft.

Boeing is the world's second-largest arms manufacturer. In July, President Donald Trump awarded Boeing the contract to build two new Air Force One aircraft for the president's travels. Trump bargained the price down to $3.9 billion and did away with the previous light blue and white design.

Race for the best weapons

The most reliable customer for the American armaments industry is the US Army, which is constantly in the market for new weapons and is able to afford extremely expensive systems such as aircraft carriers.

The arms race with countries such as Russia and China also fuels business: Lockheed Martin is currently developing an expensive "hypersonic missile" that can bypass conventional radar systems. Russia and China already have long-range missiles of this kind that fly at multiple speeds of sound. The arms race now also includes space, which Trump wants to dominate with a future "space force." In the coming year, the US intends to invest the record sum of $716 billion in armaments.

Apart from the US, only a few European companies can compete in the top positions, including the Airbus Group, in which Germany also has a stake. Airbus produces the breakdown-prone transport aircraft A400M for several European armies.

Great Britain remains the largest weapons manufacturer in western Europe, followed by France. The British mega-group BAE Systems, which has more than 83,000 employees, is the only European manufacturer to make it into the top 5 in the world. BAE Systems is involved in the construction of the European fighter aircraft Eurofighter Typhoon, which is also sold to countries such as Saudi Arabia.

Read more: German-Saudi weapons deals

Russian, Turkish firms on the upswing

In 2017, Russian defense companies, which are benefiting from Putin's modernization program for the army, made strong gains. State-owned Almaz-Antey, Russia's largest armaments company, has for the first time made it into SIPRI's top 10. Turkey is also arming itself: President Recep Tayyip Erdogan's strategy of becoming less dependent on arms imports has boosted Turkish arms manufacturers' profits by 24 percent.

According to the Stockholm researchers, three Chinese companies should also be among the top players. However, since they publish little reliable information on their arms sales, they have not been included in the list.

Four German companies

Among the world's 100 largest arms manufacturers are four German firms, including Rheinmetall, Thyssenkrupp and Krauss-Maffei Wegmann, which manufacture submarines, ships, tanks and armored vehicles for the German armed forces. They also sell them abroad. All three companies increased their profits in 2017.

New on the list is the fourth German firm, Hensoldt, based near Munich, which manufactures radars and sensors for electronic warfare. All in all, however, arms sales have little significance for German foreign trade, as they account for less than 1 percent of total German exports.