"We will continue working with the regulators and industry in the development of innovative solutions that make investing more accessible and more affordable to more consumers."
The companies which did not respond to FTAdviser included Lloyds Banking Group, Nationwide and FinEx Capital Management, a London-based hedge fund.
Anthony Morrow, chief executive of Evestor, said the advice unit had been helpful in addressing his company's questions about regulation and said it wasn't necessarily the fault of the FCA if some companies took longer to bring their services to market, or chose not to do so at all.
He said: "If a company delays its progress, this can be for a whole range of reasons, and may not be directly linked to the FCA’s advice unit. The reasons can range from not having the right proposition to lacking appropriate funding."
Simon Bussy, director at financial services consultancy Altus, agreed that it would be unrealistic to expect a 100 per cent success rate from the advice unit and said it was a way in which the FCA had been "exemplar" compared to regulators in other countries.
He added that many robo-advisers would have to overcome the scale, reach and brand of the existing players in the financial services market.
Mr Bussy said: "The existing financial services ‘robo’ sector is increasingly busy and competitive – the banks and other well-known financial services brands will typically aim to develop in-house or partner with a well-established enterprise technology solution, meaning the ‘disruptors’ will need to look elsewhere for distribution partners.
"Rather than continually creating propositions that merely mimic the existing sales process, we need businesses to really start innovating, to re-imagine what the future world of personal financial management might look like."