SJ Berwin's German arm is on course to hit a £20m turnover this year after initial figures indicate a revenue boost of around 25 per cent.
The firm's profit per equity partner (PEP) is also on the rise and is set to exceed £700,000, up from £660,000 last year.
German partner Rudiger Knopf said: "The high retention rate could be one of the secrets of profitability."
Only two associates have left the firm in Germany in recent years.
SJ Berwin has ambitious expansion plans for the country and is looking to hire partners in real estate and corporate.
IP head Stefan Krueger, who joined this year from Freshfields Bruckhaus Deringer, said the rising profits were attracting interest from top partners. "We're becoming very attractive to laterals, including partners at magic circle firms," said Krueger.