(ShareCast News) - Full year net asset value at John Laing Infrastructure Fund fell slightly to 108.4p from 109.3p, but the company still increased its second half dividend by 1.04% to 3.41p a share for an annual return of 6.75%.The company said it was "not unreasonable to expect greater volatility in the share price over the coming months" ahead of the June referendum on the UK's membership of the European Union, although there was evidence that it could benefit from any uncertainty as "investors see listed-infrastructure as a 'safe haven' in times of market turbulence".The company said a decision to leave the EU could impact UK gilt rates and the government's credit rating.Underlying portfolio growth was 8.34% while pre-tax profits fell to £47m from £67.2m. The company received £73.3m in cash from investments, £4.3m ahead of project forecasts."It is pleasing to announce another solid set of results for 2015. Since the end of the year, we have made our first investment in the Spanish market via a stake in the Barcelona Metro Stations project and agreed the acquisition of two further UK social infrastructure projects from John Laing Group," the company said."The secondary public/private partnership experienced something of an adjustment in geographical focus in 2015. The UK market for secondary projects was relatively inactive compared to previous years, whilst the western and southern European markets were particularly active.""Our team was invited to tender for over 50 projects in these markets alone. Secondary market transactions in North America and the Asia-Pacific region were fewer in number, however, we continue to remain close to these markets as we believe in the medium term they still remain important sources of opportunities for growth."