Group 1: Report Overview - The report is the Bond Research Weekly for the 4th week of September 2025, focusing on bond market analysis from the perspective of institutional behavior [2][9] Group 2: Investment Rating - Not provided in the report Group 3: Core Viewpoints - The behavior of funds is crucial in the bond market, with their net purchases strongly correlated with interest rate trends. The instability of funds' liability side has increased due to the new sales fee regulations, and the impact of the regulations' implementation should be closely monitored [4][15] - The three institutional behavior changes (funds having nothing left to sell, brokerages closing short positions, and banks "picking up bargains") are favorable for the bond market. Future interest rates may decline due to funds repurchasing bonds, banks increasing allocations, and brokerages closing positions. Currently, interest rate products have a higher probability of success than Tier 2 and credit bonds [4][15] Group 4: Summary by Directory 1. Re - examination after Interest Rate Breakthrough 1.1 Three Changes in Institutional Behavior and Future Outlook - Funds are "sold out": Since Q3, funds have continuously reduced duration. As of September 26, 2025, the median duration of medium - and long - term bond funds (including leverage) dropped to 2.8 years, and the cumulative net purchase of ultra - long treasury bonds (over 10Y) by funds has been negative since early September [3][9] - Brokerages are closing short positions: The borrowing volume of the top three active 10Y treasury bonds remains volatile, while that of 10Y CDB bonds has decreased, indicating brokerage short - position closing before the holiday [10] - Banks are "picking up bargains": Since August, joint - stock banks have continuously bought old 10Y treasury bonds, acting as a "buffer" during the bond market correction. Recently, Tier 2 and perpetual bonds have corrected rapidly, and funds are selling Tier 2 bonds more aggressively [3][14] 1.2 Yield Curve - Treasury bond yields generally increased. On a week - on - week basis, the 1Y yield decreased by 1bp, the 3Y yield increased by 3bp, the 5Y yield changed less than 1bp, the 7Y yield increased by 1bp, the 10Y yield changed less than 1bp, the 15Y yield increased by 1.5bp, and the 30Y yield increased by 2bp. In terms of percentiles, the 1Y dropped to the 10% percentile, and others had various percentile changes [16][18] - CDB bond yields also generally increased. The 1Y yield decreased by 0.5bp, the 3Y yield increased by 2bp, the 5Y yield increased by about 2.3bp, the 7Y yield increased by 4.6bp, the 10Y yield increased by 1.1bp, the 15Y yield increased by about 4.6bp, and the 30Y yield increased by 4.9bp. Percentiles also had corresponding changes [18] 1.3 Term Spread - The spread between treasury bonds and CDB bonds (1Y - DR001, 1Y - DR007) showed a differentiated trend, and the term spread generally widened [19] 2. Bond Market Leverage and Funding Situation 2.1 Leverage Ratio - From September 22 to September 26, 2025, the leverage ratio fluctuated and decreased. As of September 26, it was about 107.06%, up 0.32pct from last Friday and down 0.04pct from Monday [23] 2.2 Repurchase Transactions - From September 22 to September 26, the average daily trading volume of pledged repurchase was about 7.3 trillion yuan, up 0.1 trillion yuan from last week. The average daily trading volume of overnight pledged repurchase was 5.55 trillion yuan, down 0.72 trillion yuan month - on - month. The average overnight trading volume ratio was 75.72%, down 11.92pct month - on - month [27][28] 2.3 Funding Situation - From September 22 to September 26, bank - based fund lending first increased and then decreased. On September 26, the net lending of large and policy banks was 4.09 trillion yuan, and joint - stock, city, and rural commercial banks had a net borrowing of 0.28 trillion yuan. The main fund borrowers were brokerages, and money market funds' lending decreased. DR007, R007, 1YFR007, and 5YFR007 all fluctuated and increased, with different changes compared to last Friday [30] 3. Duration of Medium - and Long - Term Bond Funds 3.1 Overall Duration - From September 22 to September 26, the median duration of medium - and long - term bond funds was 2.68 years (de - leveraged) and 2.79 years (including leverage). On September 26, the median duration (de - leveraged) remained unchanged from last Friday, and the median duration (including leverage) decreased by 0.01 year [41] 3.2 Duration by Bond Fund Type - As of September 26, the median duration of interest - rate bond funds (including leverage) dropped to 3.53 years, down 0.01 year from last Friday; the median duration of credit bond funds (including leverage) dropped to 2.52 years, up 0.01 year from last Friday. The de - leveraged durations also had corresponding changes [44] 4. Category Strategy Comparison - As of September 26, the Sino - US spread generally narrowed, and the implied tax rate (10Y CDB - treasury bond spread) narrowed at the short end and widened at the medium - and long - ends [48] 5. Bond Lending Balance Changes - On September 26, the lending concentration of active 10Y treasury bonds and 10Y CDB bonds increased, that of secondary active 10Y CDB bonds and active 30Y treasury bonds decreased, and that of secondary active 10Y treasury bonds remained unchanged. Except for brokerages, all other institutional lending concentrations increased [50]