The top seven law firms in Ireland had revenues of more than €720m between them last year.
The earnings, calculated by UK-based market analysts, are an indicator of the rude financial health of the country's main firms, six of which have been ranked in Europe's top 50 in terms of revenue.
Financial information is closely guarded by Irish law firms, which are under no obligation to publish accounts as they are not limited companies.
In fact only one major firm here, Mason Hayes & Curran, publishes financial data.
However, a market report by 'The Lawyer', a specialist publication focussing on the business of law, was able to estimate revenue levels based on a number of key indicators.
Top of the pile was Arthur Cox, which had turnover or fee income of €144m last year. The report ranked the firm 15th in Europe in terms of revenue, in a list which excluded UK firms.
A&L Goodbody (€138.3m) was ranked 17th, McCann Fitzgerald (€121m) was in 25th place, while Matheson (€115m) was ranked 27th. Of the other top Irish earners named in the report, William Fry (€88.4m) was ranked 40th, Mason Hayes & Curran (€77m) was 47th and Dillon Eustace (€36.5m) was ranked 92nd.
In comparison, the highest-earning law firm in Europe was Garrigues. The Spanish firm's revenues were €349.4m.
Separate research by the Irish Independent indicates that although the top firms earned millions from work for State bodies, the vast bulk of their revenues came from private sector clients.
Around 5pc of their combined income, some €35.5m, came from the public purse.
The market report described Ireland as "the least transparent jurisdiction in Europe" from a data collection perspective. Analysts used indicators such as headcount growth, workflows and the type of work each firm does when estimating revenues.
All of the firms told analysts 2016 was a good year, but equally all said work slowed ahead of the UK vote to leave the EU.
The report estimated Arthur Cox's revenues rose 7pc, with its lawyers bringing in an average of €415,000 each in fees.
The firm employs 794 staff in offices in Dublin, Belfast, London, New York and Silicon Valley, of whom 347 are qualified lawyers. It has long been a "go to" legal firm for State bodies, earning €33m in fees over several years for advice on the banking crisis. Figures compiled by the Irish Independent show the firm's largest public sector clients last year included the State Claims Agency, which paid €826,587 in fees, the HSE (€646,802), Dublin City Council (€640,000), DCU (€684,785) and Nama (€430,000).
Some €9.6m was paid by public bodies to the law firm and a linked company, Arthur Cox Consultancy Services.
At least €6.5m of this went to the law firm, but the ultimate destination of funds paid to the consultancy company is unclear. It was contracted to manage legal services for the HSE up to March of last year, receiving €2m, but the sum included fees, outlays and VAT in respect of 26 law firms which provided legal services to HSE.
A breakdown of those payments was not made available.
A further €1.1m in legal fees was paid by Tusla to the law firm and the consultancy services company, but the breakdown is again unclear.
Ireland's second biggest law firm, A&L Goodbody, was paid €4.4m in fees by public bodies last year, around 3pc of its overall revenues. Its main State client was Nama, which paid the firm €2.3m in fees. Other large clients included the State Claims Agency (€807,001), the Irish Strategic Investment Fund (€304,979) and Tallaght Hospital (€235,510). The firm's revenues rose 4pc last year.
It employs 731 staff, of whom 344 are qualified lawyers, and has offices in Dublin, Belfast, London, New York, San Francisco and Palo Alto.
The country's third biggest firm, McCann Fitzgerald, was paid €6.3m by public bodies last year for advice on legal and regulatory issues.
By far its biggest State client was Transport Infrastructure Ireland, which paid €2.76m for legal services.
Other clients included the National Transport Authority (€667,413) and the Road Safety Authority (€512,316).
The firm has 240 solicitors and offices in Dublin, London, New York and Brussels.