Explanation

Over-the-counter (OTC) derivatives are privately negotiated contracts between two parties, while exchange-traded derivatives are standardized contracts traded on organized exchanges.

Key differences in transparency:

1. OTC Derivatives:

   • Privately negotiated between counterparties
   • Terms are not publicly disclosed
   • No central clearing (typically)
   • Limited price transparency
   • Counterparty risk is not publicly known

2. Exchange-Traded Derivatives:

   • Standardized contracts
   • Prices are publicly quoted and visible
   • Central clearing through clearinghouses
   • High price transparency
   • Daily mark-to-market and margin requirements

Why OTC derivatives have lower transparency:

• OTC markets lack the centralized price discovery mechanism of exchanges
• Transaction details are not reported to a central repository (though post-2008 reforms have increased reporting requirements)
• There's no public order book showing bid-ask spreads
• Counterparty identities and positions are not publicly disclosed

Regulatory context: Post-2008 financial crisis reforms (Dodd-Frank Act, EMIR) have increased transparency in OTC markets through trade reporting requirements, but OTC derivatives still remain less transparent than exchange-traded derivatives.

Therefore, the correct answer is A. lower.