The company set up an office in Northern Ireland three years ago.
The new jobs aimed at legal graduates will be created over the next five years, taking its Belfast workforce to almost 500.
Enterprise Minister Arlene Foster said the announcement reflected the company's "very positive experience" in Northern Ireland.
She said the salaries would contribute almost Â£3m a year to the local economy.
Invest NI is offering grants of Â£860,000.

Graham, 21, played the last half an hour of Tuesday's 1-0 home defeat by Huddersfield, after 15 months out with a cruciate knee ligament injury.
"I thought he really livened the game up and got some bums off seats when he came on," Stearman, 29, told BBC WM.
"If he can stay fit then he'll be a force to be reckoned with next season."
Centre-back Stearman is approaching the end of his loan spell from Fulham, having originally left Molineux for Craven Cottage in 2015.
He returned to Wolves last summer but says he is waiting, like a large number of other players, on managerial decisions before knowing where his future lies.
"There's plenty of players up and down the country who don't quite know what's going to happen next year," he said.
"A lot of people are just waiting for the end of the season before they sort out what and who they need."

The officer was taken to hospital where his condition was described as "stable", a Merseyside Police spokesman said.
He said the force was investigating an "assault of a member of staff at HMP Altcourse on Wednesday".
The BBC understands the attack took place in a transfer area and the inmate was on remand facing serious charges.
Director for HMP Altcourse Steve Williams said: "We continue to support the officer and his family."

Gurmehar Kaur has been receiving threats and abuse after her campaign against a right-wing student union.
But, Sehwag's tweet was directed at an earlier campaign, when she said her father, a soldier who died in Kargil, was killed by war, not Pakistan.
He tweeted a picture of himself holding a sign saying, "I did not score two triple centuries, my bat did."
It has been retweeted more than 20,000 times and received 33,000 "likes" since then, with many, including Bollywood actor Randeep Hooda praising the tweet.
However, others have condemned what they have called "bullying".
Cricketer defends wife against trolls
Why are Indian women being attacked on social media?
The timing of Sehwag's tweet has also been called into question, given the level of abuse Ms Kaur has been facing for her campaign against the Akhil Bharatiya Vidyarthi Parishad (ABVP), a right-wing student union, following a clash at Delhi University's Ramjas college.
The Delhi commissioner for women has directed the police to provide her with protection following the nature of abuse directed against her. They have also directed the police to initiate criminal action against those targeting her online.
The international law firm, Allen and Overy, is creating 100 new jobs in Belfast.
[NEXT_CONCEPT]
Fit-again winger Jordan Graham will add an extra dimension to Wolves' attack next season, according to team-mate Richard Stearman.
[NEXT_CONCEPT]
A prison officer has had his neck slashed by an inmate at a prison on Merseyside, the BBC understands.
[NEXT_CONCEPT]
Former India cricketer Virender Sehwag is being accused of trolling a student on Twitter.