floor在这是什么意思?下面段落中出现了好几个floor,As the Federal Reserve Cuts Interest Rates,a 'Floor' Keeps Credit Card Companies From Following AlongDespite falling interest rates,a growing number of consumers are paying the same

floor在这是什么意思?下面段落中出现了好几个floor,As the Federal Reserve Cuts Interest Rates,a 'Floor' Keeps Credit Card Companies From Following AlongDespite falling interest rates,a growing number of consumers are paying the same
floor在这是什么意思?
下面段落中出现了好几个floor,
As the Federal Reserve Cuts Interest Rates,a 'Floor' Keeps Credit Card Companies From Following Along
Despite falling interest rates,a growing number of consumers are paying the same — or even more — to borrow on their credit
cards.
The majority of credit cards on the market have variable,or floating,rates.Theoretically,that means that as the Federal
Reserve lowers its federal funds rate — the latest cut took place this month — card holders should also see their borrowing
costs fall.
In reality,though,banks often set a "floor" that credit card rates can't fall below,and in many cases,that floor has
already been reached,analysts say
Wells Fargo（富国银行）,HSBC（汇丰银行）,Discover,SunTrust and National City have a floor on at least some of their
credit cards.Wachovia,meanwhile,limits how far its penalty interest rate — applied to consumers who pay late twice in a
row — and cash advance rate can drop.But the bank imposes no minimum interest rate on credit card purchases.
Others,including Bank of America,American Express and U.S.Bank,say they have no floors on credit card rates.Chase and
Citigroup（大通银行和花旗集团）,meanwhile,declined to disclose whether they have this policy
Imposing a floor on credit card rates allows the bank to "continue lending even in challenging environments," says Todd Morgano,a spokesman for National City

floor在这是什么意思?下面段落中出现了好几个floor,As the Federal Reserve Cuts Interest Rates,a 'Floor' Keeps Credit Card Companies From Following AlongDespite falling interest rates,a growing number of consumers are paying the same
尽管美联储调低了利率,表面上看持卡人的借款成本应该相应有所下降,但是因为一些银行根据自身经营和抗风险能力上的特殊性在美联储基准利率之上还设有自己的信用卡借款利率的最低值标准（两者之差可以理解为安全垫,起到保证银行更加稳健运营的作用）.上文中,floor一词指的就是各银行为保证自身稳健运行而设定的信用卡贷款利率的下限.注：各家银行的floor可以不尽相同.很多银行在实际业务中已经达到了自身的floor水平,因此,对于这些银行的持卡人而言,只要其信用卡所在银行的floor不下调,即使美联储下调了基准利率,他的信用卡贷款成本也不会下降.