The co-founder and chief executive of The Mill has pledged his future to the London-based post company after it emerged that the business could be sold.

Mergers and acquisitions specialist Harris Williams was last week tasked with reviewing the business, but The Mill chief executive Robin Shenfield said it was not working to a specific plan of action or timescale.

However, he conceded that private-equity firm Carlyle, which acquired a majority stake in The Mill in 2007, “probably won’t own it forever because it’s not their model; they come into a business and help it to grow”.

“All The Mill has done so far is appoint an advisor to examine what a future platform for continuing to grow the business might look like,” added Shenfield. “Conjecture about the value of the business or what might happen is extremely previous.”

He told Broadcast that he had sent an email to The Mill staff to assure them there were no plans to change the management team. “This is not about management changes or people disappearing from the company,” he explained.

Peter Savage, managing director at broadcast and media finance and business management firm Azule, said that if the business was sold the only likely purchaser would be another venture capitalist company.

He added that he was “highly surprised” by initial reports of a £150m valuation. “The company made £3.3m profit last year, and people rarely pay a 50x multiple. The next 18 months will be a better time to sell than the last two years, but it might just be a flushing tactic; they may say £150m, but in reality it may be they are ready to sell for £80m.”

Shenfield said the reason for the review was to establish “how to keep growing and developing the business”, which has 450 staff across London, New York and Los Angeles and turnover in 2009 of £49.8m.

“The deal with Carlyle was to execute the strategy we had, which involved broadening the business in terms of breadth of operations we had in advertising,” he added.

“One of the things we worked on was expanding the business in the US, particularly Los Angeles, and now we are looking at the next platform for growing the business.”

Shenfield revealed to Broadcast that The Mill is due to open a new office in Los Angeles, having outgrown its Santa Monica base. The new premises are expected to be open by late spring or early summer.