摘 要本文探討了聯準會買賣國債的主要情形、券種和期限選擇、對國債市場的影響等三個關鍵細節。聯準會買賣國債一般分流動性調節和曲線管理兩類情形,前者聯準會定期依據存量國債的待償期分佈情況分散選擇操作券種,並避免購買國債期貨交割券等部分券種;後者聯準會集中選擇操作期限與券種。流動性調節情形中聯準會儘可能避免對國債市場產生影響,曲線管理情形中對市場預期和曲線形態產生了影響。對中國帶來三點啟示:一是未來中國人民銀行可能會階段性結合曲線管理情形進行公開市場操作,二是公開市場操作要根據情形或目標選擇不同選取操作券種與期限,三是實施公開市場操作要結合市場溝通與一定體量的連續操作才可能實現曲線管理情形的操作目標。聯準會買賣國債的主要情形不考慮量化寬鬆(QE),聯準會買賣國債一般分為流動性調節和曲線管理兩類情形,前者最終政策目標單一、以聯邦基金利率為中介、以吞吐基礎貨幣為工具、由貨幣市場利率向長端利率傳導,後者需兼顧多元政策目標、以國債利率為中介、以大體量扭曲操作為工具直達長端利率。根據聯準會官網的介紹,兩類情形均屬永久性公開市場操作,均由紐約聯儲公開市場操作台執行交易,通過聯準會FedTrade交易平台向24家一級交易商採用多價、競爭性拍賣方式開展,紐約聯儲通過官網發佈每期操作收到的報價總額、實際發生的交易總額等資訊。QE與曲線管理存在近似的地方,二者異同見表1。一是政策目標單一的流動性調節情形。聯準會公開市場交易台一般每月買賣國債,在價格型政策工具有效的條件下,以調節銀行準備金為手段使貨幣市場利率達到目標水平,再通過利率傳導使貨幣供應量和實際利率適應就業與通膨目標。根據紐約聯儲官網國債購買常見問題,公開市場操作台每月第九個工作日發佈該月公開市場操作時間表等資訊,包括計畫操作金額、操作日期、時間、證券類型、到期日以及最高操作金額等。如當月不進行國債買賣操作,公開市場操作台將提前在紐約聯儲官網公告。二是多元政策目標下的曲線管理情形。聯準會曾在1961年、2011年先後開展過曲線管理操作,均為應對國際收支和國內就業雙重目標矛盾下的曲線扭曲操作,一方面提升短端利率避免資本(黃金)大規模流出和國際收支逆差,另一方面壓降長端利率促進經濟增長和就業。兩次操作都希望對國債收益率曲線“壓長提短”,縮窄曲線期限利差,在利率傳導難以奏效的情況下通過大體量集中買賣直達長端利率,均為特定情況下平衡不同宏觀政策目標的權宜之計,在發佈公告或集中連續買賣後也都起到了一定效果,但需財政協同以避免供給衝擊,且最終都隨著宏觀環境的變化而退出或失效。聯準會買賣國債的券種和期限選擇流動性調節情形中聯準會選取的國債種類較分散,一般與存量國債的期限分佈大致成比例。根據紐約聯儲官網國債購買頁面(Treasury Purchase)資訊,在執行月度的小額國債買賣時,公開市場操作台購買的國債種類較多,主要包括名義付息債券、通膨保護債券(TIPS)、浮息債券(FRN)等,且與尚未償還的國債總量大致成比例,將購買的債券根據種類和期限不同分為8個組別(見表2),以每個組別過去12個月存量的移動平均為權重發起操作,並每3個月更新各組別權重分配。表3展示了截至2024年1月1日不同待償期存量美國國債規模及佔比,其為當前公開市場操作選券的參考。此外,公開市場操作台明確迴避部分券種,包括在回購中稀缺價值較高的特定抵押品、新發行的名義債券以及國債期貨合約中最便宜可交割證券(CTD),以避免對回購、國債期貨等市場的外溢影響,也不交易到期日4周內的名義付息債券、到期日1年內的TIPS以及本息分離債券(STRIPS)等,避免快速到期後的頻繁贖回或展期操作。曲線管理情形中聯準會集中選擇操作期限與券種。以2011年曲線管理為例,聯準會在2011年9月至2012年末以平均每周112.5億美元(每月450億美元)的規模購買剩餘期限為6年至30年的中長期國債,約佔當時美國流通中長期國債總金額的0.61%,佔彼時美國期限為6年及以上存量國債平均每周交易額的9.26%,券種基本為名義付息債券,期限與券種的選擇較為集中。截至2012年末,聯準會累計買入6670億美元中長期國債,約佔彼時美國流通的中長期國債總額的8%,顯著提高了聯準會公開市場操作帳戶中持有國債的平均久期。聯準會買賣國債對國債市場的影響流動性調節情形中聯準會儘可能避免對美國國債市場產生影響。根據紐約聯儲官網國債操作常見問題,常備永久性公開市場操作目的是測試執行聯邦公開市場委員會現有和潛在政策指令的營運準備情況,調節銀行準備金,借助國債市場的規模和深度進行流動性調節,避免影響國債市場定價,主要通過控制貨幣供給和實際利率以匹配經濟發展水平。2019年至今,小額公開市場操作2多數情況下月買入金額為1.5億美元,不對國債市場造成影響。此外,為確保國債市場平穩,也為避免影響銀行準備金,聯準會選擇對持有的大體量到期國債進行展期(Treasury Rollover),具體操作中公開市場操作台對同類新發國債拍賣以非競爭投標方式投標,投標價格為當期國債競爭性投標最低價,投標金額等於到期國債的全部或部分,並在國債到期日結算。曲線管理情形中聯準會通過公告對市場預期和曲線形態產生影響,並通過大體量連續操作對國債市場產生影響。以1961年曲線管理為例,聯準會先後宣佈扭曲操作新政、公開聲明支援扭曲操作並宣佈購買5年期以上國債、公佈的統計資料顯示公開市場購買長期國債數量增加等6次公告,相關公告對美債市場利率預期和收益率曲線走勢產生了一定影響,短端上行和長端下行幅度均達到15個基點(BP)。再以2011年為例,聯準會單周超過112.5億美元連續購買使得長端10年期利率一個季度內下行了60BP(見圖1),階段性達到壓降長端利率的目的。總體上,聯準會扭曲操作通過公告效應和實際執行在短期內基本實現了縮短曲線期限利差的目標,且一買一賣儘可能不影響資產負債表,確保對貨幣市場或基礎貨幣流動性的中性。對中國的啟示一是中國人民銀行現階段買賣國債主要適用流動性調節情形,但可能會階段性結合曲線管理情形進行操作。2024年6月在第十五屆陸家嘴論壇上中國人民銀行行長潘功勝指出,將買賣國債定位為基礎貨幣投放管道和流動性管理工具,既有買也有賣,與其他工具綜合搭配,共同營造適宜的流動性環境。這意味著中國人民銀行當前可能將買賣國債主要定位為流動性調節手段。但同時,金融市場快速發展帶來新的挑戰,美國矽谷銀行風險事件啟示我們要從宏觀審慎角度評估金融市場狀況,要關注非銀主體大量持有中長期債券的期限錯配和利率風險,保持正常向上傾斜的收益率曲線,及時阻斷金融市場風險累積。這說明中國人民銀行或也面臨多元政策目標的權衡,一方面長端利率不宜過低,偏離金融穩定和宏觀審慎目標;另一方面,中短端利率也不宜過高甚至倒掛,影響穩增長和就業目標,要儘可能確保正常向上傾斜的曲線形態以保持對投資的正向激勵。為此,中國人民銀行可能階段性地改良聯準會曲線管理操作,反向地“壓短提長”保持曲線期限正利差,並搭配其他操作工具避免單向操作對基礎貨幣的大幅衝擊。二是根據操作情形或目標選擇不同的操作券種與期限。參考聯準會經驗,中國人民銀行未來在流動性調節情形下可根據不同待償期存量國債的分佈情況(見表4)確定並動態更新各組別操作買賣的權重,儘可能均勻操作、有買有賣,借助國債市場的規模和深度精準調節流動性、投放基礎貨幣。階段性曲線管理情形則需要錨定目標集中選擇操作期限與券種。三是要結合市場溝通與一定體量的連續操作才可能實現曲線管理情形的操作目標。參考國內外經驗,央行公告和市場溝通對長端利率有一定影響。例如,2024年7月1日中國人民銀行公告將面向部分公開市場業務一級交易商開展國債借入操作,當日10年期國債收益率快速上行6BP。參考聯準會2011年曲線管理的運算元據,聯準會連續單周購買當時美國國內流通中中長期國債總金額0.61%的速度實現了趨勢性目標,據此大致測算中國要達到階段性效果單周買入規模可能需要270億元以上3,並且需要貨幣財政協調配合,及時評估宏觀環境變化後穩妥退出。 (債券雜誌)The Three Key Details of the Federal Reserve's OMO of Treasury Bonds and the Enlightenment for ChinaZhang Chao, Zheng MufanAbstractThis paper discusses the three key details of the US Federal Reserve (the “Fed”) trading in Treasury securities, namely, the main circumstances of trading, the selection of security types, and both maturities and impact on Treasury market. The Fed trades Treasury securities generally under the following two scenarios, liquidity intervention, or yield curve management. In the former, the selection of securities for each regular purchase plan is determined on a pro rata basis, based on the proportion of outstanding Treasuries in each maturity range, and excluding certain types of securities, such as securities that are cheapest to deliver into active Treasury futures contracts. In the latter, the types and maturities of securities that the Fed trades are determined in a concentrated manner. In the liquidity intervention scenario, the Fed tries not to affect Treasury market conditions. In contrast, operations under yield curve management scenario would have impacts on both market expectations and shape of yield curve. The inspirations to China are as follows. First, the People’s Bank of China (PBOC) may conduct open market operations (OMOs) in due course under yield curve management scenario. Second, the types and maturities of securities to be traded in an OMO should be determined by the corresponding scenario or objectives. Third, continuous trading with a certain scale is necessary to achieve the objective of OMO under yield curve management scenario.Main Circumstances of the Fed Trading in Treasury SecuritiesRegardless of quantitative easing (QE), Treasury trading of the Fed are generally conducted under two scenarios: liquidity intervention or yield curve management. The former serves the sole purpose of promoting the transmission of interest rates from money market to long term yield, by utilizing federal funds rate as an intermediary, and the scale of monetary base as an instrument. The latter needs to take into account multiple policy objectives, uses the Treasury securities rate as an intermediary and uses large-scale Operation Twist as an instrument that directly influences the long-term interest rate. According to the Fed’s website, both circumstances are permanent open market operations, with transactions executed by The New York Fed's Open Market Trading Desk (the Desk). The Desk will conduct purchases of Treasury securities via FedTrade, the Desk’s proprietary trading system, using multiple-price, competitive auctions with approved counterparties, which are the 24 primary dealers authorized by the New York Fed. The New York Fed publishes information such as the total amount of quotations received and the total amount of transactions executed for each operation on its website. There are some similarities between QE and curve management. See Table 1 for their similarities and differences.First, under liquidity intervention scenario with sole policy objective, the Desk generally conducts Treasury trades monthly, to meet the objective of matching money supply and real interest rate with target employment rate and inflation rate, through interest rate transmission mechanism by utilizing level of bank reserve as a facility to adjust money market rate to target level. According to the ‘FAQs: Treasury Purchases’ section on New York Fed’s website, the Desk will release its tentative schedule of purchase operations on or around the ninth business day of each month. The tentative schedule will include information on the planned amount, upcoming operation dates, times, security types and maturities, and maximum purchase amounts. If no purchase would be conducted for the upcoming month, the Desk will communicate such information as well..Second, under yield curve management scenario with multiple policy objectives, the Fed carried out yield curve management operations in 1961 and 2011, which were both Operation Twists with intention to achieve the contradictive objectives of both balance of payments (BOP) and domestic employment targets. On one hand, the rise in short-term interest rate would prevent both large-scale capital (gold) outflows and BOP deficit to happen. On the other hand, lowered long-term interest rate would boost economic growth and employment rate. Both operations were to “lower long-term yields and raise short-term yields” of Treasury yield curve, narrowing the term spread of Treasury yield curve, in order to intervene long-term interest rates directly, through large-scale purchases when interest rate transmission mechanism is ineffective. Both operations were expedient measures to maintain balance between different macroeconomic policy objectives under certain market conditions, both worked out to a certain extent after the operation was announced or centralized and continuous trading was carried out. However, coordination from financial policy was required to avoid Treasury supply shocks. The operations ended through an exit or expiration as the macro environment changed.Selection of Security Types and Maturities by the Fed in Its Treasury Securities TradingIn the case of liquidity intervention, purchases of Treasury securities by the Fed are conducted across a range of maturities and security types in rough proportion to the universe of Treasury securities outstanding. According to ‘FAQs: Treasury Purchases’ section on New York Fed’s website, in the monthly small-scale trading in Treasury securities, purchases may be conducted in nominal coupon securities, bills, Treasury Inflation-Protected Securities (TIPS), and Floating Rate Notes (FRNs), on a pro rata basis based on the distribution of each maturity categories of outstanding Treasury securities. The purchased securities are distributed across eight sectors (see Table 2), based roughly on the proportional par amount of Treasury securities outstanding in each sector, using the 12-month average and updated every three months. Table 3 shows the size and percentage of outstanding US Treasuries specific to the time to maturity as at January 1, 2024, serving as a point of reference for the current open market operations. In addition, The Desk will refrain from purchasing securities that are trading with heightened scarcity value in the repo market for specific collateral, newly issued nominal coupon securities, and securities that are cheapest to deliver into active Treasury futures contracts, to avoid spillover effects on repo, Treasury futures and other markets. The Desk also will not purchase securities with 4 weeks or less to maturity and TIPS with one year or less to maturity and separate trading of registered interest and principal of securities (STRIPS), to avoid frequent redemption or rollover operations at maturity.In the case of yield curve management, the Fed focused its operations on security types and maturities. Taking the curve management in 2011 as an example, the Fed purchased $11.25 billion of medium and long-term Treasury securities, mainly nominal coupon securities, with 6 to 30 years of time to maturity per week ($45 billion per month) from September 2011 to the end of 2012, accounting for approximately 0.61% of total outstanding medium- and long-term Treasuries at that time, or 9.26% of the average weekly trading volume of Treasuries with time to maturity equal or longer than 6 years at that time. The types and maturities of securities purchased were concentrated. As end of 2012, the Fed had accumulatively purchased $667 billion of medium- and long-term Treasury securities, accounting for approximately 8% of the total outstanding medium- and long-term US Treasuries at that time, significantly raised the average duration of Treasury securities held in the System Open Market Account (SOMA).Impact of the Fed’s Treasury Securities Trading on the Treasury Securities MarketIn the case of liquidity intervention, the Fed exerts all efforts to avoid making impact on Treasury market. According to ‘FAQs: Treasury Outright Operations’ section on New York Fed’s website , the purpose of the permanent open market operations is to test the operational readiness to implement existing and potential policy directives from the Federal Open Market Committee (FOMC), adjust bank reserves and adjust liquidity leveraging on the size and depth of the Treasury market while avoiding affecting the market pricing of Treasury securities. The operations are mainly to adjust both the amount of money supply and the real interest rate to match the level of economic development. From 2019 to date, the small value open market operations2 were mostly conducted with monthly purchase size of USD150 million, eliminating the impact on Treasury market. In addition, to ensure stability of the Treasury securities market and to avoid affecting bank reserves, the Fed has chosen “Treasury Rollover” for maturing large holdings of Treasury securities. Specifically, the Desk will bid for the auctions of similar newly issued Treasury securities in a non-competitive manner. The bidding price is the lowest of the competitive bids for current Treasury securities, in an amount equal to all or a portion of the maturing Treasury securities, that will settle on the maturity date of the maturing Treasury securities .In the case of curve management, the Fed influences the market expectations and shape of yield curve by publishing announcements, also influences the Treasury securities market through large-scale continuous operations. Take the yield curve management in 1961 as an example, the Fed successively published six announcements, including the launch of a new Operation Twist policy, a statement of supporting the Operation Twist and purchasing 5-year and long-term Treasury securities, and increase in purchases of long-term Treasury securities as shown by published statistics. These announcements had a certain impact on the interest rate expectations and yield curve movements in the US Treasury market, with short-term yields rising and long-term yields falling by 15 basis points. In 2011, for example, the Fed’s weekly continuous purchases of more than $11.25 billion brought the 10-year Treasury yield down by 60 basis points in a quarter (see Figure 1), achieving the goal of lowering the long-term yield for a period of time. In general, the Fed’s Operation Twist managed to achieve the goal of narrowing the term spread of Treasury yield curve in the short run through announcements and actual implementation, and the purchases and sales avoided affecting the balance sheet where possible, thereby ensuring the neutrality to the money market or the liquidity of the base money.Inspirations to ChinaFirst, the People’s Bank of China (PBOC) may conduct OMOs in due course under yield curve management scenario. At the 15th Lujiazui Forum in June 2024, PBOC Governor Pan Gongsheng pointed out that the purchases and sales of CGBs should serve as a channel for base money supply and a liquidity management tool, and should work with other instruments to create a proper liquidity environment. This means that the PBOC may now mainly position the CGB trading as a means of liquidity adjustment. However, the rapid development of financial markets has posed new challenges to PBOC. The failure in risk management Silicon Valley Bank in the United States has revealed the necessity of assessing the financial market conditions from a macro-prudential perspective, paying due attention to the maturity mismatches and interest rate risks of the large holdings of medium- and long-term bonds by non-bank entities and keeping the yield curve normally sloping upwards, so as to prevent any risk buildup in financial markets in a timely manner. This indicates that PBOC may also face tradeoffs among multiple policy objectives. On one hand, long-term interest rates should not be on a significantly low level or deviate from both financial stability and macro-prudential objectives. On the other hand, short- and medium-term rates should not be too high or even inverted to an extent of negatively affecting the objective economic growth and employment stability. It is imperative to ensure the yield curve is upward sloping to maintain positive incentives for investment. To this end, PBOC may improve the Fed’s yield curve management operations for an appropriate period of time, maintaining positive yield curve’s term spreads by “lowering short-term yields and raising long-term yields”, with utilizing other operation tools to avoid any substantial impact of one-way operations on the base money.Second, the types and maturities of securities to be traded in an OMO should be determined by the corresponding scenario or objectives. With reference to the experience of the Fed, PBOC may determine and dynamically update the weights of trading operations of each group based on the distribution of outstanding CGBs based on to time to maturity (see Table 4) under the liquidity intervention scenario in the future, operate as evenly as possible in buying and selling directions, and precisely adjust the liquidity and supply the base money leveraging on the size and depth of the CGB market. In the case of temporary yield curve management, it is necessary to select the security types and maturities suitable for the corresponding objectives of the operation.Third, continuous trading with a certain scale is necessary to achieve the objective of OMO under yield curve management scenario. According to domestic and foreign experience, announcements and market communications of Central Banks have certain impact on long-term yields. For example, on July 1, 2024, the PBOC announced the permission of borrowing CGB by selected primary dealers in OMOs, leading to a sharp rise of 6 basis points in the 10-year CGB yield. As shown by the data from Fed’s yield curve management operation in 2011, the Fed achieved the trendy objective by continuously purchasing 0.61% of the total outstanding medium- and long-term Treasury securities in one week. Accordingly, it is roughly estimated that China may need to purchase more than RMB27 billion3 in one week to meet the objective, with coordination of both monetary and fiscal policy, and further exit this temporary move after timely assessment of changes in the macro environment.