A brand new survey has for the first time ranked the brand strength of alternative legal service providers—and the Big Four accounting firms aren't on top.

The report, by legal market research company Acritas, instead named Thomson Reuters as the legal market's strongest alternative brand, ahead of PricewaterhouseCoopers, EY and Deloitte. The final Big Four member, KPMG, placed sixth, ranking behind Axiom.

Acritas interviewed over 1,000 in-house counsel at billion-dollar organizations across more than 50 countries and asked them to name the most well-known legal service providers, excluding law firms; those that they perceived most favorably; and those that are the most innovative.

Acritas CEO Lisa Hart Shepherd said that while traditional law firms are still “the preferred option” for most in-house counsel, they only have limited time to adapt their businesses in the face of growing competition from alternative service providers.

“It is out of date to consider legal services from lawyers as not competing with those from nonlawyers or through technology solutions,” she said. “There will always be room in the market for boutique high-end advisers, but for the large firms, they need to consider these broader needs and develop smarter, more flexible and cost-effective services, or risk losing market share to a whole host of new competitors they have largely discounted to date.”

The top 10 ranking is rounded out by LexisNexis, which has a strategic partnership with The American Lawyer parent company ALM; flexible resourcing pioneer Lawyers On Demand, which spun out from U.K.-based law firm Berwin Leighton Paisner in 2012; information services company Wolters Kluwer; and intellectual property management company CPA Global.

The Big Four accounting firms have in recent years invested particularly heavily in legal services. The group now collectively employ about 8,500 attorneys globally, while The American Lawyer recently revealed that PwC is launching a U.S. law firm.

PwC actually led the Acritas survey for top-of-mind awareness. Shepherd said that the Big Four's scale and visibility as leading professional services organizations “lends a significant advantage to their brand platform.”

But Thomson Reuters took the top spot overall after being named by clients as their most favored nontraditional legal brand. It also scored three times as high as any other alternative provider for innovation, with LexisNexis a distant second. Nearly three-quarters of clients said that they haven't seen any meaningful innovation from external legal advisers, however. Surprisingly, of those that were recognized as innovative, only one-third were alternative service providers. The rest were traditional law firms.

While this marks the first time that Acritas has measured the brand strength of alternative legal service providers, the company has ranked law firms for more than a decade. Its latest Global Elite brand index, published earlier this week by The American Lawyer, revealed that Baker McKenzie's brand is now twice as strong as any other law firm's.

Baker McKenzie has topped Acritas' Global Elite Brand Index ever since the report's inception in 2010, and this year widened the gap to the rest of the market. Its brand strength is now more than double that of second-placed DLA Piper and five times that of Sidley Austin and White & Case, which both ranked 15th.

Acritas' law firm survey highlighted that while alternative service providers are becoming a more significant part of the market, that has yet to translate into brand strength. EY was the highest-placed alternative legal service provider in the global elite ranking, but was nowhere near the leading law firms, ranking only 77th.

But in another sign that suggests the Big Four will become increasingly serious competitors to Big Law firms, EY would rank among the top 20 elite law firm brands if the responses were limited to in-house lawyers under the age of 40.

Chris Johnson is based in London, where he writes about global law firms and the business of law. Contact him at [email protected]. On Twitter: @chris_t_johnson.