1. Report Industry Investment Rating - No information provided regarding the industry investment rating. 2. Core Viewpoints of the Report - The US bond market is the world's largest, influencing global capital flows and investor decisions. The report comprehensively analyzes its current situation, focusing on the classification, structure, and scale of credit bonds [10][11]. 3. Summary According to Relevant Catalogs 3.1 US Bond Market Overview 3.1.1 Global Fixed - Income Market - In 2024, the total global fixed - income market size was $145.06 trillion, with a year - on - year growth of 2.43%. The US fixed - income market accounted for 40.10% of the global total, reaching $58.2 trillion (BIS口径), 2.22 times that of the EU market and 2.32 times that of the Chinese mainland market [11]. - China's mainland fixed - income market had the fastest growth rate in 2024 at 9.31%, followed by Singapore (7.02%), Hong Kong (5.94%), and the US (5.23%) [15]. 3.1.2 US Fixed - Income Market - **Stock Scale**: As of Q1 2025, the US fixed - income market stock was $47.44 trillion (SIFMA口径), a 1.35% increase from the end of 2024. Treasury bonds had the highest balance at $28.58 trillion, accounting for 60.25%, followed by corporate bonds ($11.36 trillion, 23.94%), municipal bonds ($4.23 trillion, 8.92%), federal agency bonds ($1.98 trillion, 4.18%), and money market instruments ($1.28 trillion, 2.70%) [17]. - **Issuance Scale**: In H1 2025, the US fixed - income market issuance was $5.70 trillion, a 14.21% increase compared to the same period in 2024. Treasury bond issuance was the largest at $2.43 trillion, accounting for 42.69%, followed by corporate bonds ($1.17 trillion, 20.58%) and MBS ($0.87 trillion, 15.19%) [25]. - **Daily Average Trading Volume**: In H1 2025, the daily average trading volume was $1.54 trillion, a 19.34% increase compared to the full - year 2024 average. Treasury bonds had the largest trading volume at $1.11 trillion, accounting for 71.97%, followed by MBS ($3497.06 billion, 22.77%) and corporate bonds ($575.01 billion, 3.74%) [32][34]. - **Daily Average Turnover Rate**: The US Treasury market had the highest liquidity, with a daily average turnover rate of 3.32% in 2024. MBS was second, with a peak turnover rate of 2.73% in 2020. Corporate bonds, municipal bonds, federal agency bonds, and ABS had long - term turnover rates below 1% [38]. 3.2 US Credit Bond Market Overview 3.2.1 US Municipal Bond Market - **Stock and Primary Issuance**: From 2014 - Q1 2025, the US municipal bond stock showed a fluctuating upward trend, reaching $4.23 trillion in Q1 2025. From 2011 - 2024, public - issued revenue bonds were the main issuance type, with the issuance of public - issued general obligation bonds increasing first and then decreasing, and private - placement bonds having a relatively small scale [47]. - **Secondary Trading**: In H1 2025, the total trading volume reached $1.92 trillion, with 8.7038 million transactions, increasing by 18.99% and 26.04% respectively compared to the same period. The turnover rate recovered to 0.32% in 2024 after reaching a low in 2021 [60]. - **Holder Structure**: Individual investors were the largest holders, accounting for 45.24% in Q1 2025, followed by mutual funds, which accounted for 28.28% [65]. - **Rating and Default Situation**: As of the end of 2024, about 92% of municipal bonds had an A - grade or higher. The median rating was Aa3. The default rate was low, with the five - year and ten - year average cumulative default rates for all municipal bonds being 0.08% and 0.15% respectively [67][79]. 3.2.2 US Corporate Bond Market - **Stock and Primary Issuance**: The corporate bond stock continued to expand, reaching $11.36 trillion in Q1 2025, a year - on - year increase of 3.67%. In H1 2025, the total issuance was $1.17 trillion, a 5.14% year - on - year increase. Investment - grade bonds accounted for 86.34% of the issuance in H1 2025 [84][88][90]. - **Secondary Trading**: The daily average trading volume increased year by year, reaching $759.83 million in H1 2025, a 19.20% increase compared to 2024. The turnover rate was relatively stable from 2015 - 2024, slightly increasing to 0.45% in 2024 [96]. - **Holder Structure**: Foreign investors were the largest holders in Q1 2025, accounting for 28.55%, followed by life insurance companies (22.81%) and mutual funds (15.06%) [102]. - **Rating and Default Situation**: Corporate bond ratings were generally lower than municipal bonds. In 2024, the number of Baa - rated corporate bonds was the largest. The global corporate debt default amount increased in 2024, with the US having the largest number of default companies. Distressed debt exchanges were the main cause of default [107][113]. 3.3 US Other Bond Market Overview 3.3.1 US Treasury Market - **Stock Scale**: As of H1 2025, the US Treasury stock was $28.65 trillion, with medium - term Treasury bonds having the largest share at $15.07 trillion [125]. - **Issuance Scale**: In H1 2025, the issuance was $14.42 trillion, a 3.02% year - on - year increase, and the net increase was $0.34 trillion, a $0.30 trillion year - on - year decrease. Short - term Treasury bonds accounted for 83.14% of the issuance in H1 2025 [129]. - **Trading Volume**: The daily average trading volume increased year by year, reaching $1.11 trillion in H1 2025, a 21.74% year - on - year increase [131]. 3.3.2 US Federal Agency Bond Market - **Stock Scale**: From 2014 - 2021, the scale decreased, and then began to recover after 2022, reaching $1.98 trillion in Q1 2025 [136]. - **Issuance**: The issuance was affected by multiple factors and fluctuated significantly year - by - year. The Federal Home Loan Banks had the largest issuance share [142]. - **Trading Volume**: The daily average trading volume showed a fluctuating downward trend, decreasing from $6.05 billion in 2014 to the range of $3 - 4 billion in recent years [142]. 3.3.3 US MBS and ABS Markets - **Stock Scale**: MBS achieved fluctuating growth with government guarantees, while ABS shifted to mortgage - type underlying assets due to the contraction of unsecured assets [147]. - **Issuance**: In H1 2025, MBS issuance was $86.5381 billion, and ABS issuance was $21.4659 billion. Automobile loan - backed securities became the highest - issuance variety in ABS in H1 2025 [153]. - **Trading Volume and Turnover Rate**: MBS had a larger trading scale, and its daily average turnover rate was higher than that of ABS, reaching 2.40% and 0.09% respectively in 2021 [155][159].