A similar trend has shaken up the investment banking industry in the last decade. Many veterans of big Wall Street banks have opened or joined boutique financial advisory firms that cater to clients who have grown disillusioned with what they view as inadequate — and sometimes conflicted — services provided by the biggest investment banks. Examples include Moelis & Company, Greenhill & Company and Perella Weinberg Partners.

In the legal world, one appeal of boutiques is that landing jobs in the white-collar practices at top law firms is getting harder. That’s partly because of aggressive hiring in recent years and partly because corporate clients are trying to cut their spending on legal services.

“A lot of firms have filled their white-collar practices. Firms are spending more time to better market themselves, and there is less demand for white-collar attorneys,” said Jack Zaremski, president of Hanover Legal Personnel Services in New York. “There is still a market for highly credentialed lawyers, but big law firms do not have the same need that they once did.”

After working as an assistant United States attorney for the Eastern District of New York, James Walden took a job at Gibson Dunn & Crutcher, a global law firm, where he led its white-collar practice.

After a spell there, Mr. Walden said, “I very much wanted to build something of my own with a strong culture but without the trappings of beautiful paintings or celebrity speakers at retreats, or a lot of internal competition.”

Three years ago, he helped found Walden, Macht & Haran, which specializes in white-collar litigation and government investigations. The firm has grown to 23 lawyers, representing financial institutions as well as cable, media and entertainment companies.

“This is a time when Big Law is at a crossroads,” Mr. Walden said. “We’re trying a new model, which means we can charge about 60 percent of what a Big Law firm would charge for the same services.”