Given the pressure to avoid being crushed by the firms above or ousted by the firms below, it is in many ways surprising that the rising 25 aren't paying more heed to the Legal Services Act (LSA) and the potential for change it could bring.

To date, a limited few have expressed interest in making fundamental changes to their business, including taking advantage of outside investment permitted under the Act. While undoubtedly all firms are watchful of the LSA's impact, most are unwilling to be the sacrificial lamb that tries it first.

"We have done a bit of work on the Legal Services Act internally to see whether we are interested in it, in particular the investment side. The answer is no. There would be too much of a culture shift and the rewards don't outweigh the upheaval," says Speechly Bircham managing partner Michael Lingens.

Although opening the door to outside investors in particular leaves most firms cold, firms such as Weightmans and Pannone – the main firms within the 51-75 bracket to operate volume practices – are well placed to capitalise on provisions in the Act allowing other non-legal entities to break into the arena (so-called Tesco law).

Weightmans, in common with firms such as Beachcroft, Russell Jones & Walker and Shoosmiths, has set up subsidiary businesses separate from its core practices. The firm currently operates a personal injury claims business known as Converge as well as an employment law arm called HR Rely.

Weightmans managing partner Patrick Gaul comments: "I have been to umpteen talks on alternative business structures and never thought, 'this applies to us'. We are conscious our market is being invaded by people with different structures – like Capita. We stroked our chins and talked about it but decided it was not for us. The nearest we have done is to set up Converge and HR Rely – they are very much part of Weightmans, but under a different banner and marketed differently. They are a pointer to the future."

But where the Act has clearly had an impact is in making firms more corporate-minded. Of the 25 firms, a number including Dickinson Dees, Farrer & Co, Cobbetts and Morgan Cole have already adopted legal disciplinary partnerships, bringing non-lawyer financial directors, human resources managers and IT directors into their partnerships. A further swathe of firms, including Bircham Dyson Bell, TLT, Russell Jones & Walker and Speechly Bircham are considering similar moves.

While Cobbetts and Russell Jones have expressed some enthusiasm for opportunities in the age of Tesco law, generally, firms of this size have been conservative regarding innovations to their model. RSG Consulting founder Reena SenGupta, who has overseen five years of research for the FT Innovative Lawyers Report, notes that firms like Mishcon de Reya, TLT and Blake Lapthorn have experimented with new client tools and outsourcing. But the breed as a whole has plenty of room to embrace innovation.