The five men sued by the Omagh families are all alleged members of the Real IRA.
Four of them have been found liable for the bombing. One of them, Seamus McKenna, was cleared of liability.
None of them appeared in court, and they did not provide evidence.
Michael McKevitt is serving 20 years in the Republic for directing terrorism
The alleged founder and leader of the Real IRA.
The 54-year-old, from Blackrock in County Louth, is serving a 20 year prison sentence in the Republic of Ireland.
He was jailed in August 2003 by the Special Criminal Court in Dublin for organising terrorist activities for the Real IRA.
He was the first person in the history of the state to be convicted of that offence, which was created in response to the Omagh bomb.
Handing down the verdict, Mr Justice Robert Barr described McKevitt as "a long-time republican extremist".
He lost an appeal against his conviction last July.
McKevitt was awarded full legal aid to defend himself in the Omagh civil case.
Liam Campbell is wanted in Lithuania over an arms plot
A farmer from Upper Faughart, near Dundalk, in County Louth.
In 2001 he was jailed in the Republic for membership of an illegal organisation.
A raid on his home by Irish Special Branch officers uncovered a bunker underneath his bathroom containing £2,000, walkie-talkies, a radio scanner, two large paper body disposable suits and "what could be construed as bomb-making equipment, but no explosives."
He is wanted in Lithuania over a plot to smuggle weapons to Ireland, and he is in custody pending extradition proceedings.
A barrister for the Lithuanian authorities told a Belfast court in May that Campbell faced charges which "in essence amount to the acquisition of a large quantity of firearms, ammunition, explosive devices and substances including automatic rifles, projectors, detonators and timers, and to bring them from the Republic of Lithuania to Ireland".
Seamus Daly was beaten in County Monaghan in June
A 34-year-old builder from Cullaville, County Monaghan.
In 2004 he was sentenced to three and a half years in jail in the Republic after he admitted being a member of an illegal organisation.
BBC Panorama reporter John Ware, who has investigated the Omagh bombing, has said police believed Daly was the "hands-on" organiser.
The programme also said that mobile phone evidence linked Daly to car bombings in Lisburn and Banbridge as well as Omagh.
In August 2008 he and Colm Murphy lost an appeal against exceptional legal aid being granted to the Omagh victims' families.
Earlier this month he required hospital treatment after he was beaten up by a number of men in Carrickmacross, County Monaghan.
Seamus McKenna has spent time in jail for the possession of explosives
A 56-year-old labourer from County Armagh.
He served six years in jail after he was convicted of possessing explosives.
In September, the civil inquiry heard that McKenna was "drowning his sorrows" in a pub run by Colm Murphy in Dundalk on the night of the Omagh bomb.
An employee of Murphy's, Patrick Morgan, said he "assumed it was something to do with Omagh when he was on the drink".
Lawyers acting for the Omagh families believe that McKenna used one of two mobile phones obtained by Colm Murphy which form a central plank of the plaintiffs' case.
Colm Murphy is awaiting a retrial for conspiracy to cause the Omagh bomb
A builder and publican, 55, from Dundalk in County Louth.
In 1984 he spent a year in jail in the United States for trying to buy missiles, rifles and submachine guns.
In January 2002 he was sentenced to 14 years in jail for conspiracy to cause the Omagh bombing.
The conviction was overturned on appeal, and he is awaiting a retrial.
A Dublin court heard in May that Murphy called the bombing "a tragedy" and "an atrocity" while in Garda custody.
Detective Garda James Hanley told the court that Murphy denied ever having been in Omagh.
But he said Murphy said he would have to consult with his solicitor when he was asked how his phone came to be in the County Tyrone town.