本文建構一個具有金融體系和投資市場的貨幣搜尋模型，來探討在何種情況中，央行會決定在原有的傳統貨幣政策基礎上再加進非傳統貨幣政策。Ferraris and Watanabe(2012)考慮投資市場的流動性，說明貨幣有助於緩解流動性短缺的問題，但並未考慮金融風暴衝擊與貨幣政策的影響。本文拓展其模型，考慮有金融風暴衝擊和非傳統貨幣政策的情況，證實出主要變數-利率、貨幣數量、通膨、投資、消費等的變動方向都會與Gertler and Karadi(2011)的DSGE模型之衝擊反應函數所帶出的主要變數變動方向一致。

本研究有以下三點發現: 一為利率是否有觸及ZLB，視銀行貸放意願決定之；當銀行貸放意願低到為零時，若央行沒有觀察到該現象，持續使用以利率調控為主的傳統貨幣政策，反而更會陷入ZLB問題。二為在傳統貨幣政策下，當利率為零時，由於銀行無法將央行注入貨幣轉成信用貸放出去，預持現金限制發生，消費財與投資財購買量將萎縮；在非傳統貨幣政策下，當利率為零時，由於可以跳脫銀行體系貸放意願的干擾，貨幣持有量增加，有效刺激消費與投資行為的成長。三為在低通膨環境，且銀行貸放意願為正時，傳統和非傳統貨幣政策對於經濟體的影響將更有效，貨幣數量的增加不僅大幅減少利率，也可以刺激消費和投資；高通膨環境，阻礙貨幣政策的成效，增加的貨幣數量會降低短期利率，但由於通膨過高，消費和投資有可能無法增加，反而還會萎縮，也就是長期利率可能不降反增，且非傳統貨幣政策由於無法立即退場，該政策造成的傷害將大於傳統貨幣政策。

A model of investment market integrates financial intermediation theory with the monetary search framework. We use the model to explore in what circumstances that the central bank uses unconventional monetary policy rather than conventional monetary policy. Ferraris and Watanabe (2012) presents liquidity in investment market, and indicates the role of money to help ease liquidity shortage problems, but the article did not study the impact of the financial turmoil and monetary policy. Our article expands the model, considering the effect of the central bank using (un)conventional monetary policy to combat the financial crisis. We demonstrate that the direction of change of key variables - interest rate, the quantity of money, inflation, investment and consumption - is consistent with Gertler and Karadi (2011) of the DSGE model.

In this paper we address the following findings. First, whether interest rates have touched ZLB depends on the bank lending channel. When bank lending willingness is low to zero and the central bank did not observe this phenomenon to constant use conventional monetary policy, it is more likely to fall into ZLB problem. Second, when interest rates are close to zero in conventional monetary policy and the bank credit can’t be loaned out, the quantity of money decreases; and further, deflationary pressure will occur. When interest rates are close to zero in unconventional monetary policy and the policy excludes the impact of bank lending channel, the quantity of money effectively increases; and further, deflationary pressure can be lifted. Third, when bank lending willingness is positive in a low inflation environment, both conventional and unconventional monetary policies affect the economy more effectively and bring about the quantity of money to increase. In addition, its increase is not only significantly to reduce the short-term interest rate, but also stimulates consumption and investment. Monetary policies are not effective in a high inflation environment. Though the quantity of money reduces short-term interest rates, consumption and investment come to a recess as a result of a high inflation. Besides, unconventional monetary policy can’t exit immediately, so it causes even larger(greater) damage than conventional monetary policy.

一、 中文參考文獻

1. 劉邦海 (2009)，「Fed信用寬鬆政策對各國處理信用緊縮問題之啟示」，國際金融參考資料，第58輯，中央銀行經濟研究處，頁42-101。
2. 高超洋 (2009) ，「日本零利率及量化寬鬆政策與當前美國貨幣政策之比較」，國際金融參考資料，第58輯，中央銀行經濟研究處，頁102-134。
3. 黃富櫻 (2010)，「由全球金融風暴綜觀貨幣政策角色的轉變」，國際金融參考資料，第59輯，中央銀行經濟研究處，頁1-47。
4. 蕭翠玲 (2011)，「日本央行之貨幣政策與穩定金融措施」，國際金融參考資料，第62輯，中央銀行經濟研究處，頁84-113。
5. 謝儀悌 (2011)，「美國對準備金付息及其貨幣政策效果」，國際金融參考資料，第62輯，中央銀行經濟研究處，頁47-83。
6. 陳旭昇和湯茹茵 (2012)，「動態隨機一般均衡(DSGE)模型在貨幣政策制定上的應用: 一個帶有批判性的回顧與展望」，經濟論文叢刊，第40卷第3期，頁289-323。
7. 陳裴紋 (2012)，「參加瑞士中央銀行基金會研究中心舉辦之「貨幣經濟學進階議題」研習課程報告」，行政院及所屬各機關出國報告。
8. 蔡炯民 (2013)，「「出席2013年國際清算銀行(BIS)年會」心得報告「非傳統貨幣政策」」，行政院及所屬各機關出國報告。
9. 張志揚 (2012)，「美國非傳統貨幣政策之採行及其影響」，國際金融參考資料，第63輯，中央銀行經濟研究處，頁23-46。
10. 張德存和李映宣 (2013)，「流動性、資產與廠商投資決策」，經濟論文叢刊，第41卷第4期，頁477-506。

二、 英文參考文獻

1. Acharya and Nagvi (2012), “The Seeds of a Crisis: A Theory of Bank Liquidity and Risk Taking Over the Business Cycle.” Journal of Financial Economics 106(2), 349-366.
2. Bernanke, Ben S. and Alan S. Blinder (1988), “Credit, Money, and Aggregate Demand,” American Economic Review 78, 435-439.
3. Bernanke, Ben S. and Mark Gertler (1995), “Inside the Black Box: The Credit Channel of Monetary Policy Transmission,” Journal of Economic Perspectives 9, 22-48.
4. Berentsen, Camera and Waller (2007), “Money, Credit and Banking.” Journal of Economic Theory 135, 171-195.
5. Committee on the Global Financial System (2011), “Global Liquidity – Concept, Measurement and Policy Implications.” CGFS Papers 45, November 2011.
6. Cecchetti and Schoenholtz (2011), “Monetary Policy: Stabilizing the Domestic Economy.” Money, Banking and Financial Markets - Global edition 3, Published by McGraw-Hill.
7. Dietrich Domanski, Ingo Fender and Patrick McGuire (2011), “Assessing Global Liquidity.” BIS Quarterly Review, 57-71, December 2011.
8. Eric Girardin and Zakaria Moussa (2011), “Quantitative Easing Works: Lessons from the Unique Experience in Japan 2001-2006.” Journal of International Financial Market, Institutions and Money 21, 461-495.
9. Heike Schenkelberg and Sebastian Watzka (2013), “Real Effects of Quantitative Easing at the Zero Lower Bound: Structural VAR-based Evidence from Japan.” Journal of International Money and Finance 33, 327-357.
10. Holmstrom and Tirole (1998), “Private and Public Supply of Liquidity.” Journal of Political Economy 106, 1-40.
11. Harun Alp, Selim Elekdag and Subir Lall (2011), “Did Korean Monetary Policy Help Soften the Impact of the Global Financial Crisis of 2008-2009.” IMF Working Paper, January 2011, International Monetary Fund.
12. Kazuo Ueda (2012), “The Effectiveness of Nontraditional Monetary Policy Measures: The Case of the Bank of Japan.” Japanese Economic Review 63(1), 1-22.
13. Kazuo Ueda (2012), “Japan’s Deflation and the Bank of Japan’s Experience with Nontraditional Monetary Policy.” Journal of Money, Credit and Banking 44(1), 175-190.
14. Kleopatra Nikolaou (2009), “Liquidity (Risk) Concepts: Definitions and Interactions.” ECB Working Paper 1008, February 2009, European Central Bank.
15. Leo Ferraris and Makoto Watanabe (2012), “Liquidity Constraints in a Monetary Economy.” International Economic Review 53, 255-277.
16. Miguel Molico (2006), “The Distribution of Money and Prices in Search Equilibrium.” International Economic Review 47(3), 701-722.
17. Mark Gertler and Peter Karadi (2011), “A Model of Unconventional Monetary Policy.” Journal of Monetary Economics 58, 17-34.
18. Martin Bodenstein, James Hebden and Ricardo Nunes (2012), “Imperfect Credibility and the Zero Lower Bound.” Journal of Monetary Economics 59, 135-149.
19. Morten L Bech, Leonardo Gambacorta and Enisse Kharroubi (2012), “Monetary Policy in a Downturn: Are Financial Crisis Special.” BIS Working Paper 388, September 2012, Bank for International Settlements.
20. Ricardo Lagos and Randall Wright (2005) “A Unified Framework for Monetary Theory and Policy Analysis.” Journal of Political Economy 113(3), 463-484.
21. Robert Barbera (2009) “The Cost of Capitalism: Understanding Market Mayhem and Stabilising Our Economic Future.” Published by McGraw-Hill 1.
22. Ricardo Reis (2010), “Interpreting the Unconventional U.S. Monetary Policy of 2007-09.” NBER Working Paper 15662, January 2010, National Bureau of Economic Research, Inc.
23. Stephen D. Williamson (2012), “Liquidity, Monetary Policy, and the Financial Crisis: A New Monetarist Approach.” American Economic Review 102(6), 2570-2605.
24. S. Pelin Berkman (2012), “Bank of Japan’s Quantitative and Credit Easing: Are They Now More Effective.” IMF Working Paper, January 2012, International Monetary Fund.
25. Stephen Williamson and Randall Wright (2011), “New Monetarist Economics: Methods.” Handbook of Monetary Economics 3A(2), 25-96.
26. Shigeru Iwata and Shu Wu (2006), “Estimating Monetary Policy Effects When Interest Rate are Close to Zero.” Journal of Monetary Economics 53, 1395-1408.
27. Te-Tsun and Yiting Li (2013), “Money, Credit and Monetary Policy.” Worker Paper, January 2013, National Taiwan University.
28. Vasco Curdia and Michael Woodford (2011), “The Central-bank Balance Sheet as an Instrument of Monetary Policy.” Journal of Monetary Economics 58, 54-79.
29. Yacine Ait-Sahalia, Jochen Andritzky, Andreas Jobst, Sylwia Nowak and Natalia tamirisa (2012), “Market Response to Policy Initiatives During the Global Financial Crisis.” Journal of International Economics87, 162-177.