The responsibility and choice of what assets a firm invests in rests solely with the firm's management, Bulley said, as it is best placed to determine which assets fit the business strategy and meet its policyholder protection obligations.
The PRA would only want to ensure that the insurer is adequately capitalised relative to the risks it is running, and is able to understand and control those risks, Bulley said.
"The prudent person principle under Solvency II places responsibility on the insurer to judge what investment best fits the risk profile of its organisation," Bulley said.
The regulators role, he said, is to "satisfy itself as to the appropriateness and prudence of that judgement, bearing in mind the overall standards and calibration requirements of Solvency II".
The information and data requirements in Solvency II should help inform an insurer's decision on whether to invest in infrastructure, Bulley said, and the PRA will continue to review the evidence as the new regime beds down.
Investments by insurers in infrastructure assets drew heightened prominence earlier this year when the European Insurance and Occupational Pensions Authority (EIOPA) published a discussion paper on insurer infrastructure investments in March, said insurance law expert Rabbani Choudhury of Pinsent Masons, the law firm behind Out-Law.com.
"The public consultation period for responding to the paper ended on 26 April 2015. The next step is for EIOPA to prepare technical advice to the European Commission on the identification and calibration of infrastructure investment risk categories under Solvency II, which it says it will do this summer," Choudhury said.
"Insurers will welcome the PRA taking a neutral stance on what levels of exposure they have to infrastructure investments. It is only right that it should be left to insurers to exercise their own judgement in making their own investment decisions. While this places greater responsibility on an insurer, they have the greatest understanding of the impact and the risks involved in making such investment decisions," he said.
The new Solvency II EU-wide regulatory regime comes into force across the EU on 1 January 2016, and will apply to more than 400 retail and wholesale UK insurance firms and to the Lloyd's insurance market. The new rules set out broader risk management requirements for insurers, require firms to hold enough capital to cover all their expected future insurance and reinsurance liabilities and introduce a new "fit and proper" test for firms' senior managers.
The PRA published final rules setting out how it will implement Solvency II in the UK earlier this month. At the time, chief executive Andrew Bailey said that large insurers should prepare for a "fundamental change" to the way in which they are regulated.