Serial sector investor Luke Johnson has invested c.£1.4m in buying a 9.75% stake in the small stockbroker Arden Partners, raising speculation that he would look at listing some of the companies he has backed through Risk Capital Partners, including Patisserie Valerie.

The declaration of Johnson’s stake pushed Arden’s shares 15.9% higher to 73p, 9p more than he paid for them

Johnson said: “I think smaller-company stockbrokers are going to have a great year. This will be the best year for new issues for at least a decade. There is a huge return of interest among institutional investors. The specialist smaller company funds have had inflows of cash. Great news for the market.”

Executive deputy chairman Jonathan Keeling said: “We are very pleased to have Luke on board and his network of private equity contacts will expand Arden’s reach among smaller companies.”