A private military company (PMC) provides specialized expertise or services of a military nature. The hiring of professional soldiers is a common practice throughout history. Though these soldiers were once known as mercenaries, such companies prefer to be known as private military contractors, Private Security Contractors (PSCs), Private Military Corporations, Private Military Firms, Military Service Providers, and generally as the Private Military Industry, in order to avoid the negative stigma often associated with mercenaries.
The services and expertise cover those typically found in governmental military or police forces, but most often on a smaller scale. While PMCs often provide services to train or supplement official armed forces in service of governments, they are also employed by private firms. However, contractors who use offensive force in a war zone could be considered unlawful combatants, thereby referring to the "concept" being implicitly mentioned in the Geneva Conventions and explicitly specified by the US Military Commissions Act.
Private military companies supply bodyguards for the Afghan president Hamid Karzai and pilot armed reconnaissance planes and helicopter gunships as part of Plan Colombia.  They are licensed by the United States Department of State, they are contracting with foreign governments, training soldiers and reorganizing militaries in Nigeria, Bulgaria, Taiwan, and Equatorial Guinea. The PMC industry is now worth over $100 billion a year.
PMCs are also known as security contractors, although this term usually refers to individuals employed or contracted by PMCs. Services are mainly rendered for other business corporations, international and non-governmental organizations, and state forces.
Private military companies are sometimes grouped into the general category of defense contractors. However, most defense contractors supply specialized hardware and perhaps also personnel to support and service that hardware, whereas PMCs supply personnel with specialized operational and tactical skills, which often include combat experience.
The 1949 Third Geneva Convention (GCIII) does not recognize the difference between defense contractors and PMCs; it defines a category called supply contractors. If the supply contractor has been issued with a valid identity card from the armed forces which they accompany, they are entitled to be treated as prisoners of war upon capture (GCIII Article 4.1.4). If, however, the contractor engages in combat, he/she can be classified as a mercenary by the captors under the 1977 Protocol I Additional to the Geneva Conventions (Protocol I) Article 47.c, unless falling under an exemption to this clause in Article 47. If captured contractors are found to be mercenaries, they are unlawful combatants and lose the right to prisoner of war status. Protocol I was not ratified by the United States because, among other issues, it does not require "freedom fighters" to obey the convention in order to be granted its protections.
There are efforts by the nations and the industry itself to better regulate the duties of contracting states and the rights of the companies and their workforce. For example, there is a initiative by the Red Cross, the non-binding Montreux Document, or the IPOA code of conduct.
The United States State Department employs several companies to provide support in danger zones that would be difficult for conventional U.S. forces. The military employs many of them as guards to high ranking U.S. government officials in high risk areas all around the world. The term most often refers to the two dozen U.S. firms that provide services for the Pentagon and indirectly assist in overseas theaters of operation. Some contractors have served in advisory roles that help train local militaries to fight more effectively instead of intervening directly. Much of the peacekeeper training the United States provides to African militaries is done by private firms, and with the increasing absence of Western military support to international peace operations, the private sector is commonly utilized to provide services to peace and stability operations from Haiti to Darfur.
The Center for Public Integrity reported that since 1994, the Defense Department entered into 3,601 contracts worth $300 billion with 12 U.S. based PMCs. Some view this as an inevitable cost cutting measure and responsible privatization of critical aspects of a military. However, many feel this is a troubling trend, since these private companies are not directly accountable to a legislative body and may cost more than providing the same functions within the military. Seventeen of the nation's leading private military firms have contributed $12.4 million in congressional and presidential campaigns since 1999.
Another issue of concern has been the recent high-profile operation of various PMCs within the United States, specifically during the initial response after Hurricane Katrina in New Orleans. Supporters are quick to point out the stabilizing influence that the operators of these companies put into place in the first few days provided, whereas detractors have levied claims of abuse and unlawful activities. Neither side has provided much proof to back their claims, however, beyond anecdotal evidence.
Domestic operations are generally under the auspice of state or federal agencies such as the Department of Energy or the Department of Homeland Security rather than the Department of Defense. Driven by increasingly greater fears of domestic terror attacks and civil unrest and disruption in the wake of disasters, more conventional security companies are moving into operations arenas that would fall within the definition of a PMC.
On December 5, 2005, U.S. Secretary of Defense Donald Rumsfeld held a lecture dubbed "The Future of Iraq" at Johns Hopkins Paul H. Nitze School of Advanced International Studies. During a Q&A session afterwards he was asked a question by graduate student Kate Turner regarding PMCs.
Turner: "There are currently thousands of private military contractors in Iraq and you were just speaking of rules of engagement in regards to Iraqi personnel and US personnel. Could you speak to, since the private contractors are operating outside the Uniform Code of Military Justice, can you speak to what law or rules of engagement do govern their behavior and whether there has been any study showing that it is cost effective to have them in Iraq rather than US military personnel. Thank you."
Rumsfeld: "Thank you. It is clearly cost-effective to have contractors for a variety of things that military people need not do, and that for whatever reason other civilians, government people, cannot be deployed to do. There are a lot of contractors, a growing number. They come from our country but they come from all countries, and indeed sometimes the contracts are from our country or another country and they employ people from totally different countries including Iraqis and people from neighboring nations. And there are a lot of them. It's a growing number. Of course we've got to begin with the fact that, as you point out, they're not subject to the Uniform Code of Military Justice. We understand that. There are laws that govern the behavior of Americans in that country. The Department of Justice oversees that. There is an issue that is current as to the extent to which they can or cannot carry weapons, and that's an issue. It's also an issue, of course, with the Iraqis. But if you think about it, Iraq’s a sovereign country. They have their laws and they're going to govern, the UN resolution and the Iraqi laws, as well as U.S. procedures and laws govern behavior in that country depending on who the individual is and what he's doing. But I personally am of the view that there are a lot of things that can be done for a short time basis by contractors that advantage the United States and advantage other countries who also hire contractors, and that any idea that we shouldn't have them I think would be unwise."
According to the FY2007 Defense Budget appropriation bill, the text of the UCMJ has been amended to allow for prosecution of military contractors who are deployed in a "declared war or a contingency operation."
"SEC. 552. CLARIFICATION OF APPLICATION OF UNIFORM CODE OF MILITARY JUSTICE DURING A TIME OF WAR. Paragraph (10) of section 802(a) of title 10, United States Code (article 2(a) of the Uniform Code of Military Justice), is amended by striking 'war' and inserting 'declared war or a contingency operation'." 
Farah Stockman of the Boston Globe, (7 January 2007) writes: "Previously, the code applied to "persons serving with or accompanying an armed force in the field" only during a war, which US courts interpreted to mean a war declared by Congress. No such declaration was made in the Iraq conflict. Now, Congress has amended the code to apply to persons accompanying an armed force during a "declared war or contingency operation."
But the provision might also have unintended consequences, if the military chooses to use its new power to court-martial civilians. For instance, the language in the law is so broad that it can be interpreted as saying that embedded journalists and contract employees from foreign countries would also be liable under the military code. Other punishable offenses under the code include disobeying an order, disrespecting an officer, and possession of pornography in a combat zone."
In light of the above issues, some commentators have argued that there has been a recent exodus from many special operations forces across the globe towards these private military corporations. The British Special Air Service, the US Special Operations Forces  and the Canadian Joint Task Force 2 have allegedly been severely affected. Finding work in the industry is not difficult for most former soldiers as their personal network of fellow and ex-soldiers is enough to keep them informed of available contracts.
Currently in Iraq there are thought to be at least 100,000 contractors working directly for the United States Department of Defense which is a tenfold increase in the use of private contractors for military operations since the Persian Gulf War, just over a decade earlier. The prevalence of PMCs has led to the foundation of trade group the Private Security Company Association of Iraq. In Iraq, the issue of accountability, especially in the case of contractors carrying weapons is a sensitive one. Iraqi laws do not hold over contractors. Just before leaving office as head of the Coalition Provisional Authority, Paul Bremer signed Coalition Provisional Authority Order 17 where it is stated that:
Contractors shall not be subject to Iraqi laws or regulations in matters relating to the terms and conditions of their Contracts, including licensing and registering employees, businesses and corporations; provided, however, that Contractors shall comply with such applicable licensing and registration laws and regulations if engaging in business or transactions in Iraq other than Contracts. Notwithstanding any provisions in this Order, Private Security Companies and their employees operating in Iraq must comply with all CPA Orders, Regulations, Memoranda, and any implementing instructions or regulations governing the existence and activities of Private Security Companies in Iraq, including registration and licensing of weapons and firearms.
PMCs supply support to U.S. military bases throughout the Persian Gulf, from operating mess halls to providing security. They supply armed guards at a U.S. Army base in Qatar, and they use live ammunition to train soldiers at Camp Doha in Kuwait. They maintain an array of weapons systems vital to an invasion of Iraq. They also provide bodyguards for VIPs, guard installations, and escort supply convoys from Kuwait. All these resources are called upon constantly due to the war in Iraq.
Two days before he left Iraq, L. Paul Bremer signed "Order 17" giving all Americans associated with the CPA and the American government immunity from Iraqi law. A July 2007 report from the American Congressional Research Service indicates that the Iraqi government still had no authority over private security firms contracted by the U.S. government.
The new status-of-forces agreement makes it clear that Contractors are under the jurisdiction of Iraqi law.
|AirScan||Titusville, FL||US Department of Defense, US Air Force, NASA, US Forest Service, National Test Pilot School, National Response Corporation, US Department of the Interior, Bureau of Land Reclamation, Arkansas, Florida, Illinois, Louisiana, Missouri, New Jersey, Pennsylvania, and West Virginia, Maximum Protective Services, ECOPETROL: the national oil company of Colombia, Occidental Petroleum Corporation, Cabinda Gulf Oil Company (Angola), SONANGOL: national oil company of Angola||Provides airborne surveillance and security|
|Custer Battles||McLean, Virginia||Iraq and oil sector (at present, have ceased operations in Iraq)|
|DynCorp||Falls Church, VA||Iraq|
|ITT Corporation||White Plains, NY||Kosovo|
|KBR||Houston||Formerly a Division of Halliburton|
|Military Professional Resources Inc.||Alexandria, VA|
|MVM, Inc.||Vienna, Virginia||CIA and NSA contractor|
|Northbridge Services Group||Turkmenistan, Somalia, Nigeria|
|Northrop Grumman||Los Angeles|
|Triple Canopy, Inc.||Herndon, Virginia||South America, Iraq|
|Sharp End International||Mainly uses Australian and New Zealand ex-special forces instructors|
|Titan Corporation||San Diego, CA||Benin||
Triple Canopy Iraq
|Vinnell Corporation||Fairfax, Virginia||Turkey, Saudi Arabia|
|Xe Services LLC||North Carolina||Iraq & Afghanistan|
|Pathfinder Security Services||Casper, Wyoming||Oil, gas and mining sector; mainly in the US|
|G4S||Palm Beach Gardens, Florida||Paramilitary security forces of DoD, Energy Department, Savannah River Nuclear Site, and others. Commonly known in the U.S. by its former name; Wakenhut Group.|
|American Asset Protection||Los Angeles, California||US Department of Defense SAK Commodities Oil, gas and mining sector; mainly in the Iraq area. Also conducting operations in Afghanistan, Saudi Arabia and the UK.|
|Aegis Defence Services||Iraq, Afghanistan, and others|
|ArmorGroup||Now part of G4S|
|Control Risks Group||Provider of security and armed guards for British Embassies and Consulates|
|Erinys International||Joint South Africa-Britain company|
|Sandline International||Ceased operations on April 16, 2004|
India With the current volatile situation in India,and due to its proximity to Afghanistan,many companies are trying to establish a foot hold in the continent. Quite notable amongst them is CATS FAC,operating from India, in south east Asia & Middle east, they were hired by Al Gore former vice president of USA to rescue American/British employees of Live earth who were caught in Mumbai during the tragic terrorist attacks of 26/11/2008, the four civilians whose identities are a secret were rescued after a 18 hour operation personally headed by Indian Mercenary Mehul Vora owner of CATS Fac & other Personnel.