Bain Capital Specialty Finance Inc. Replay the stock market charts of BCSF day by day, back to 2003. Open long and short positions without spending any money. Bain Capital Specialty Finance, Inc. is business development company specializing in direct loans to middle-market companies. The fund seeks to invest in senior investments with a first or second lien on collateral, senior first lien, stretch senior, senior second lien, unitranche, mezzanine debt, junior securities, other junior investments, and secondary purchases of assets or portfolios that primarily consist of middle-market corporate debt. It typically invests in companies with EBITDA between $10 million and $150 million.