As you keep getting more new business (hopefully faster than the old regulars taper off and stop coming), you can tap your rate up again: it's an upward spiral.

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Home-equity lines of credit allow borrowers to tap the credit line as needed, and the rate is typically variable.

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At least one lender, Wells Fargo, is giving borrowers a break on origination and monthly servicing fees for adjustable-rate reverse mortgages, which allow homeowners to tap their home equity as they need it.

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Second, Chilean firms and banks can tap international capital markets only if two bond-rating agencies rate their paper as high as Chile's own government bonds.

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The region certainly needs to tap into every ounce of entrepreneurial spirit it has got given the highest unemployment rate in the country, and its dependence on the public sector.

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It used to be considered bad form to have to tap the Fed's discount window, where rates are about one point over the federal funds rate, or 6.25%.

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But Twitter will probably follow the example of other technology companies, basing its corporate headquarters in Dublin to take advantage of the tax rate (then hiring back-office staff) and setting up another branch in London where it can tap into a wider pool of folks who are highly skilled in software development.

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