The legal company topped the rankings for the second quarter of 2014 after multiplying its London Stock Exchange (LSE) listed clients by four on the previous quarter, totalling 91 clients.
It also came fourth in the total number of LSE clients advised and small cap/fledgling categories.
Carey Olsen chairman John Kelleher said: “Of particular note, in the quarter under review, was our work advising on the establishment of Kennedy Wilson Europe Real Estate which raised approximately £1bn and is the largest ever real estate fund to be listed on the LSE."
The Corporate Advisers Rankings Guide reports on advisers to FTSE 100, FTSE 250, AIM and small cap/fledgling clients, listing institutional advisers against their quoted clients.
The report shows rankings tables for auditors, financial advisers, financial PR advisers, law firms, registrars and stockbrokers based upon client numbers, client market capitalisation and client profitability across the main FTSE indices.
Law firms that operate within the UK legal market including offshore law firms are ranked.