Shares in the company rose 10% to 5.5p in early deals on the back of interim results that indicated the company's shares have a net asset value of 10.8p.
MBIF's investment objective continues to seek growing income distributions with capital appreciation potential in the long term by investing in a diversified portfolio of biopharma sector securities. The company said prospects for the investment “remain compelling”.
Plethora has been taken over by Regent Pacific Group, giving Port Erin a stake in Hong Kong-listed Regent.
Summit is an international biopharmaceutical company focussed on the discovery and development of novel medicines to treat the fatal muscle wasting disease Duchenne Muscular Dystrophy (DMD) and infections caused by the bacteria C. difficile (CDI).
Summit's progress has been extensively covered on Proactive Investors.
During the reporting period the company invested £94,995 in the Diabetic Boot Company, a company focused on treating diabetic foot ulcers.
Investment income in the six months to the end of 2015 was negative at £96,448 compared to £83,835 the year before.
Loss before tax widened to £184,674 from £143,388 in the same period of 2014, although given the company's focus on early-stage biopharmaceutical companies, the results are not particularly meaningful and investors tend to focus on the net asset value per share, which is currently substantially higher than the share price.
"Your board is currently considering a number of further options which show significant promise in being able to eliminate the substantial discount to net asset value in line with the investing policy adopted in November 2013," said Jim Mellon, non-executive chairman of Port Erin.