Billionaire hedge fund investor Steven Cohen has avoided paying any fines after nearly a decade of probes into widespread accusations of insider trading at his firm, SAC Capital. The Securities and Exchange Commission accused Cohen of ignoring clear signs that “should have caused a reasonable hedge fund manager to investigate” potential insider trading by his employee, Mathew Martoma. Martoma is serving a nine-year prison term after becoming the eighth employee of Cohen’s firm convicted of insider trading. But under the deal with regulators, Cohen himself is barred from managing investors’ money for just two years.