If you are interviewing for a corporate or transactional law focused position, to get an overview of the firm's practice areas, industry/sector focus, and/or niche areas.
Now that you have secured an interview, make sure to do a deep dive at the law firm's website about their corporate/transactions department(s) - look for patterns:
Chambers | Associate - this "Student's Guide to the Legal Profession" offers quick charts on diversity and rankings, and summer program projections. The Bonus Features tab for a firm often includes tips from recruiters and recent summer associates. Participation by law firm recruiters means you are seeing the firm in the way they would like to be presented to prospective summer associates, so with that caveat in mind, dig in.
Bloomberg Law offers a variety of tools to help you get an overview of a firm's practice profile -
Lexis+ Market Standards - database of publicly filed transactions with coverage of M&A for over 33,000 deals from the last ten years. Click More Filters to search by law firm.
Many leading law firms and specialty practices publish client advisories, newsletters, and other literature focused on their topical areas of expertise and business development focus (and some even assign summer associates to work on updating and adding publications). Some good sources to browse for large law firm literature:
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