May 7 (Reuters) - CION Investment Corp's CION.N net asset value per share fell in the first quarter as portfolio markdowns and weaker earnings pressured results, even as the business development company accelerated share repurchases.

Net asset value per share declined to $13.11 as of March 31 from $13.76 at December 31, after the company recorded $36.1 million in net unrealized depreciation.

CION reported a $23 million net decrease in net assets from operations. Its investment portfolio stood at $1.80 billion at fair value, compared with $1.96 billion in amortized cost, implying a fair value-to-cost ratio of about 0.92x.

Net investment income after taxes fell to $12.9 million, or 25 cents per share, from $19.3 million, or 36 cents per share. Total investment income declined to $49.5 million from $56.1 million.

CION repurchased about 1.12 million shares for roughly $9.7 million during the quarter, continuing to buy back stock at a discount to book value.

The company also made $65.6 million of new investments while receiving $37.4 million in principal repayments, resulting in net deployment despite valuation pressure.