Helical's EPRA net asset value per share fell by 1.7% to 465p in the six months to the end of September, reflecting the impact on NAV from the sale of the retirement village portfolio.
The group reported an EPRA loss per share of 5.9p (2016: earnings 4.4p).
IFRS basic earnings per share fell to 0.3p (2016: 27.8p) and IFRS pre-tax profits of £1.2m were down from £31.1m).
Chief executive Gerald Kaye said: 'The financial year to date has seen Helical make encouraging progress in executing its strategy and meeting targets.
'Following the sale announced yesterday of our retirement village portfolio for £102m, a 13% discount to book value, we have now sold the majority of our non-core holdings, with those remaining accounting for just 4% of the total portfolio.
'One Creechurch Place, London EC3 is 48% let with a further 22% under offer and good interest in the remaining space. In addition, we have achieved record rents at a number of our London investment assets.
'With the second phase of The Bower, London EC1 and One Bartholomew Close, London EC1 due for completion in Q3 2018, we are confident of their letting prospects.
'Looking forward, we will continue to seek new refurbishment and development opportunities in undersupplied markets.
'We have sold over £315m of investment assets since 1 April 2016, including the sale this week of our London office investment at C-Space, London EC1, at prices in aggregate of 2.5% above book value.
'Net proceeds have funded our capital expenditure programme and, importantly, have reduced net borrowings by £236m substantially reducing our loan to value from 55%, at 31 March 2016, to today's pro-forma ratio of 43%.
'With our portfolio of high quality London and Manchester offices and higher yielding logistics properties, we now look forward to increasing our income stream from the current contracted rents of £45m towards the portfolio's ERV of £65m as completed office space is made available to potential tenants in the next 12 months.'