Goldman Sachs BDC lower on pre-earnings downgrade

• The valuation "seems stretched," says BAML's Derek Hewitt, noting an unjustified premium to Buy-rated peers like TPG Specialty Lending (TSLX flat), and TCP Capital (TCPC -0.5%).
• He downgrades Goldman Sachs BDC (GSBD -2.9%) to Underperform from Neutral.
• Credit spreads are the primary catalyst for Goldman's generation of excess returns, but they're under pressure in more liquid markets, says Hewitt.
• GSBD reports its Q3 after the close this evening.