差別利率 - 經濟

※ 引述《liton (歐吉桑留學生)》之銘言：
: : 推 McGyver:所以我的下一個疑問是 規定開始要採用差別利率 會不會其實 04/06 13:11
: : → McGyver:效果還是一樣？ 還是只有那些高風險的人去借而已？ 04/06 13:11
: I think.. you are a student
: you are asking a question which is not a question
: In the real world, there are not economic theories everywhere.
: And never try to put all phenomena into economic theories
: -------------------------------------------------------------------
: The key risk factor is transformation.
: Transform "application form" into "score card"
: Transform "score card" into "interest rate spread"
: If you have run any econometric model,
: you would find that adjuested R square running up to 60% or 70%
: already have powerful explanatory ability.
: Suppose the adjusted R squre represtnts the forecasting
: accuracy of bad debt ratio and we have a adjusted R square of 75%.
: And the accurate bad debt ratio is 15%.
: Therefore you forecast the bad debt ratio is 11.25%
: How much margin spread should you charge if
: the current (saving) interest rate is 1%
: the recovery rate is 0%, and there is no friction cost?
: 1+1%=(1+R)(1-15%) ---> R=18%
: 1+1%=(1+r)(1-11.25%)---> r=13.8%

如果今天銀行高估壞帳率，假設銀行估的壞帳率為16%

那麼 1+1%=(1+r)(1-16%) ---> r=20.238%

這個利率相當接近一年20%的法定上限

在這個情況下，不就變成銀行會超收?

如果銀行在預估壞帳率準確的情況下，又若借方的訊息比貸方訊息多

那麼超收利率是絕對有可能的情形


我的問題是: 如果我是銀行，如果預估壞帳率是"不準"的

那麼我會傾向低壞帳率還是高壞帳率?


: The adverse selection exists because banks cannot
: identify who is the lemon; therefore banks face only
: downside risk and cannot enjoy upside benefit.
: It's no surprise banks suffer from low forecasting accuracy.
: How can you judge the credit of the debtor only by a paper?
: But it should be the destiny of the cash card (and credit card)
: Card card features its convenience and simplicity.
: If banks want to increas its forecasting accuracy
: of bad debt ratio and adopt different spread levels,
: they would enhance the credit investigation process.
: But if banks ehance the process, it is not cash card any more.
: -------------------------------------------------------------------
: The key is not adverse selection.
: Banks cannot forecast the bad debt ratio well now.
: How can they adopt different spread levels?
: So..forget the spread levels. It's only an unreachable gift.

http://www.ettoday.com/2006/04/01/320-1924094.htm

根據新聞，每個月都按時繳款的人才能享受銀行的優惠利率

所以一開始是銀行去選擇低利率的人，而不是借款人直接去找銀行


不過就liton大所言，若真的adjusted R square已經具有70%左右的解釋能力

那麼問題就變成是: 為什麼銀行事先沒辦法解決現在所謂的"卡債問題"

什麼樣的情形導致了現在的卡奴問題? 是銀行的錯還是card holder的問題?

除了從application form 到scored card到interest rate spread外

借方事前少做了什麼，或做了什麼不該做的事，讓借方的壞帳風險提高?

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謙




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