本人堅信、並一再重申，任何有意義的討論，必須有明確的議題，所涉概念，必須要有公認的定義，不可自創。

基於此，我重複一遍本人的觀點：美國目前市面通行的房貸，除去月付款小於利息的 negative mortgage，履約付款，利息結算均為單利。

本人的立場依據已於好幾個帖子中說明。不贅。此處僅引用並複習一哈複利的定義： 

"Compound interest arises when interest is added to the principal, so that, from that moment on, the interest that has been added also earns interest. This addition of interest to the principal is called compounding. " （Source: http://en.wikipedia.org/wiki/Compound_interest）

該文並特意說明：

"U.S. mortgages use an amortizing loan, not compound interest. With these loans, an amortization schedule is used to determine how to apply payments toward principal and interest. Interest generated on these loans is not added to the principal, but rather is paid off monthly as the payments are applied."

我認為以上定義灰強準確。

剛才見有同學羅列一大堆堅持房貸是複利的五味大師級別的同學，以示房貸複利派的觀點正確。給我留下灰強深刻的印象。

請允許我也介紹一位大師。關於美國房貸是單利還是複利，這位大師認為：

"There are two kinds of mortgages in the US. One accrues interest monthly, and is simple interest except when it allows negative amortization, when it is compound interest. This mortgage has no special name because most mortgages are of this type... The second kind of mortgage accrues interest daily and is always simple interest. This kind of mortgage ought to be called a "daily accrual mortgage" because that would clearly distinguish it from the standard mortgage." (http://www.washingtonpost.com/wp-dyn/content/article/2008/01/25/AR2008012501739.html)

這位大師的名字是 Jack M. Guttentag, now Professor of Finance Emeritus, formerly Jacob Safra Professor of International Banking, at the Wharton School of the University of Pennsylvania. Earlier he was Chief of the Domestic Research Division of the Federal Reserve Bank of New York, on the senior staff of the National Bureau of Economic Research, and managing editor of both the Journal of Finance (1974-77) and the Housing Finance Review (1983-89). （http://www.inman.com/buyers-sellers/columnists/jack-guttentag）

我們五味土產的大師大部分是我的朋友，學問精深博大，想象力極其轟乎，我一向敬仰。但是，在房貸單利還是複利的問題上，如果非要選擇相信誰的話，我選擇急克大師，in a heart beat。

喔，再補充一句：單利不是零利息，不是免費的午餐，銀行也沒有施捨行善。

謝謝。