Access to debt markets affects how firms provide trade credit. When firms have better access to debt, they give less trade credit to major customers, especially those with good credit ratings. This is because they have more power in the market and don't need to rely on trade credit as much. Laws that improve access to debt cause firms to expand their customer base and build stronger relationships with riskier customers. This shift leads to less investment and more borrowing by customer firms, who in turn provide less trade credit to other firms.