Accounts filed at Companies House show McGrigors had booked more than £13 million in operating profit in the first seven months of its financial year on £43.5m of turnover.
The profit before remuneration of members and profit share was £12.9m.
That put it on track to deliver a similar performance as posted in the 12 months to September 30, 2011, when it reported £71.2m turnover, almost £21m in operating profit and profit before remuneration of members and profit share coming in at £20.6m
Alongside its offices in Edinburgh, Aberdeen and Glasgow, McGrigors had UK sites in Belfast, Manchester and London plus operations in Qatar and the Falkland Islands.
The most recent accounts, covering the period between October 2011 and April 30 this year, showed McGrigors added 13 legal employees plus eight other administrative staff, although members of the partnership dipped from 95 to 91.
Overall, total headcount increased from 740 to 757.
Staff costs during the period were £18.2m, against £28.9m for the full prior year.
The profit allocated to the member with the largest entitlement was £298,000 against £495,000 for the 2011 year.
The average profit per partnership member in the seven months was £142,000 compared to the £216,000 figure in the previous 12 months.
McGrigors was headed by managing partner Richard Masters and in the accounts he said: "All areas of the practice experienced high levels of activity in the run up to the merger, despite a challenging economic background.
"Our focus on the energy, infrastructure and professional and financial services sectors has worked well and will continue in the merged firm."
A relocation of the 50-strong Aberdeen office was said to be in the pipeline and that site subsequently opened in September.
The accounts show McGrigors had reduced its overdraft from £4.7m to less than £1.6m with net debt dropping from £4.8m to £4m.
The McGrigors name, which can be traced back to the 18th century, disappeared when the Pinsent Masons merger formally completed on May 1.
The agreement created an international practice with 2500 staff.
Mr Masters is now head of client operations at Pinsent Masons.
Pinsent Masons declined to comment.
This year has seen several merger deals with the largest all-Scottish merger between Burness and Paull and Williamsons.