Marina Biotech this week announced that its stock has begun trading on the over-the-counter markets after the company was unable to meet the Nasdaq's listing requirements.

"I and our board of directors have decided, at this point, that the company is not in a position to meet the listing standards of the Nasdaq stock market,” Marina President and CEO Michael French said in a statement. “By utilizing the strengths of the OTC markets, we believe we can be in a position in the future to return to a national securities exchange if we so choose."