(ShareCast News) - Residential development group Sigma Capital has raised £20m in a share placing as it seeks to build its own portfolio of assets.The London-listed company issued 26.7m at 75p each, representing a 6.8% discount to the prior's day closing price, and said the proceeds will be invested in a portfolio of private rented assets, which would complement its existing joint ventures with Bank and Grainger.In a separate announcement on Wednesday, the group said the delivery of 927 new rental homes in the North West was ahead of schedule."Our PRS portfolio target with Gatehouse has now expanded to 10,000 new homes over the next five years," said group chairman David Sigsworth."Complementing this, we are expecting to commence our first PRS site with Grainger in the second half."Meanwhile, the group reported a 0.5% year-on-year decline in reported net assets per share to 16.7p at the end of June, while the interim pre-tax loss more than doubled to £0.41m, as revenue declined 44.4% year-on-year to £1m.However, the group stressed it only started generating income from its PRS activities in the last quarter of 2014 and that PRS income comprised the major part of first half revenues.Sigma expects its own portfolio or private rented sector assets to improve returns and generate long-term income, the company said on Wednesday, adding it expects new rental homes to produce net income in excess of £2m per year and an indicative £13m of capital uplift."We are already deploying this platform successfully with Gatehouse with the first phase of 927 PRS homes well underway," said group chief executive Graham Barnet."The development of our own portfolio will significantly enhance returns and generate additional material long-term recurring income."Sigma shares were up 0.25% to 80.70p at 1100 BST on Wednesday.