企業融資、流動性與貨幣政策

Abstract

本論文包含兩篇貨幣經濟理論研究。第一篇是以貨幣模型探討存貨和企業融資相關議題，第二篇是考量資產可抵押性探討貨幣政策和失業相關議題。

在第一篇研究中，我們考量企業因交易摩擦無法順利生產或交貨而持有存貨，藉以發展一個一般均衡模型來探討存貨與利率之間的關係。為使我們的理論模型可以解釋與存貨相關的實證發現或典型事實，我們在模型中還納入了企業融資和銀行信貸。我們的模型可以明確說明存貨與數種利率之間的關係，其中包括名目利率、實質利率和實質貸款利率。研究結果顯示，存貨分別與名目利率和實質利率呈反向關係。我們也發現名目政策利率對實質貸款利率有正向傳遞效果，這表示央行可以實施寬鬆貨幣政策來刺激經濟。然而，當不同參數的數值改變時，存貨和實質貸款利率的變動方向卻沒有特定的關聯，此一發現與部分實證結果一致，即存貨和利率之間沒有顯著關係。

在第二篇研究中，我們考量一個企業可能使用不同的資產，例如貨幣或長、短期政府公債，來購買生產投入的搜尋模型，以研究貨幣政策對消費和失業的影響。研究結果發現，傳統貨幣政策與非傳統貨幣政策是透過不同傳遞機制來影響市場流動性和經濟活動。為了提高經濟社會的總產出和就業，央行可以實施以下三種貨幣政策。其一是降低名目政策利率。此做法可以降低企業的融資成本以及購買較多的資本財。其二是增加政府公債的供給。此做法可以增加經濟社會中的抵押品數量，使企業較易取得抵押品而得以購買較多的資本財。其三是增加政府公債的可抵押性。此做法可以增加政府公債的流動性，讓企業在使用這些債券作為抵押品時能夠購買較多的資本財。由於企業在生產上可以投入更多的資本財，其生產收益也會相應增加，這使企業能夠提供更多的工資和職缺。因此，總產出、消費和就業都將有所增長。

This dissertation includes two essays. The first essay is “Inventory and Corporate Finance in a Monetary Model.” The second essay is “Asset Pledgeability, Monetary Policy, and Unemployment.”

In the first essay, we develop a general equilibrium model in which inventory arises from trade frictions, to study the relationship between inventory and interest rates. We account for corporate finance and bank credit in the model and find that our results are broadly consistent with inventory-related evidence or stylized facts. We explicitly illustrate the relationship between inventory and several interest rates, including the nominal interest rate, the real interest rate, and the real lending rate. In our model, inventory is inversely related to the nominal interest rate and the real interest rate. And we find that the nominal policy rate has a positive pass-through effect on the real lending rate, which implies that the central bank can implement an easing monetary policy to stimulate the economy. However, inventory and the real lending rate may or may not move in the same direction as parameters change. This finding is consistent with some empirical findings that there is no significant relationship between inventory and interest rates.

In the second essay, we develop a search-theoretical model in which firms use money as means of payment or short-term and long-term government bonds as collateral to finance input, to study the effects of monetary policy on consumption and unemployment. We find that conventional and unconventional monetary policy affect liquidity and economic activity with different transmission mechanisms. To improve aggregate output and employment, the central bank can implement the following three types of monetary policy. The first is to lower the nominal policy rate, which reduces the cost of financing and helps firms to purchase more capital. The second is to increase the supply of government bonds, which increases the stock of aggregate collateral and makes it easier for firms to obtain collateral and finance more capital. The third is to increase the pledgeability of government bonds, which increases their liquidity and allows firms to finance more capital as they use these bonds as collateral. Due to increased capital, firms have increased returns on production, which allows them to offer more wages and vacancies. As a result, aggregate output, consumption and employment will all increase.