Am Law 100 law firm interest in the Chicago market remains high, with a string of firm launches, boutique mergers and lateral group acquisitions in the city in the last few years. But as more firms enter the city, industry observers say, the well of firms with roughly 150 lawyers or less and which would entertain a big-firm union is drying up.

There’s a notable dearth of midsize and smaller firms remaining in the city, at least, ones that would provide a realistic talent boost to a larger firm and that would align economically, said Susan Mendelsohn, a longtime Chicago law firm recruiter and consultant.