So what is LIBOR, exactly? (Hint: It's named after London, but it's actually quite international)

So what is LIBOR, exactly? | Marketplace.org

Conforming ARMs From 2004-2006 Are Adjusting To 3 Percent

When a mortgage applicants chooses an adjustable-rate mortgage over a fixed-rate one, he accepts a risk that -- at some point in the future -- the mortgage's interest rate will rise. Lately, though, that hasn't been the outcome.

Since mid-2010, conforming mortgages have adjusted below their initial "teaser" rate consistently, giving homeowners in California and nationwide reason to ride their respective adjustable-rate mortgages out.

For example, this month, conforming 7-year and 5-year ARMs are adjusting near 3.011 percent based on the most common loan terms of 2004-2006. It's because of how adjustable-rate mortgages are structured.

Adjustable-rate mortgages follow a defined lifecycle. First, the ARM's mortgage rate is pegged; held fixed for a set number of years. This period ranges from one year to 10 years; periods of five and seven years are most common.

When the initial fixed-rate period ends, the mortgage rate then adjusts based on a pre-set formula. The formula is established by contract in the mortgage closing paperwork, and is commonly defined as:

(Adjusted Mortgage Rate) = (2.250 percent) + (Current 1-Year LIBOR)

Next, every 12 months, based on the same formula as above, the ARM adjusts again until 30 years have passed and the loan is paid is full.

It's important to recognize that in the above equation, LIBOR is a variable so as LIBOR goes, so goes your adjusted mortgage rate. And because LIBOR is ultra-low right now, adjusted mortgage rates are ultra-low, too. LIBOR is expected to stay this way until the global economy has recovered more fully. Analysts predict a higher LIBOR by mid-2012.

So, if you have an adjustable-rate mortgage that's due to reset this season, don't rush to refinance. For at least one more year, you can benefit from low rates and low payments.  As for the next adjustment, though, that's anyone's guess.

Adjustable Rate Mortgages Adjusting To 3.000 Percent Right Now

If your ARM is due to adjust this spring, your best move may be to allow it. Don't rush to refinance -- your rate may be adjusting lower.

It's because of how adjusted mortgage rates are calculated.

First, let's look at the lifecycle of a conventional, adjustable rate mortgage:

1. There's a "starter period" of several years in which the interest rate remains fixed.
2. There's an initial adjustment to rate after the starter period. This is called the "first adjustment".
3. There's a subsequent adjustment until the loan's term expires. The adjustment is usually annual.

The starter period will vary from 1 to 10 years, but once that timeframe ends, and the first adjustment occurs, conventional ARMs enter a lifecycle phase that is common among all ARMs -- regular rate adjustments based on some pre-set formula until the loan is paid in full, and retired.

For conventional ARMs adjusting in 2011, that formula is most commonly defined as:

(12-Month LIBOR) + (2.250 Percent) = (Adjusted Mortgage Rate)

LIBOR is an acronym for London Interbank Offered Rate. It's the rate at which banks borrow money from each other. It's also the variable portion of the adjustable mortgage rate equation. The corresponding constant is typically 2.25%.

Since March 2010, LIBOR has been low and, as a result, adjusting mortgage rates have been low, too.

In 2009, 5-year ARMs adjusted to 6 percent or higher. Today, they're adjusting near 3.000 percent.

That's a big shift. 

Therefore, strictly based on mathematics, letting your ARM adjust this year could be smarter than refinancing it. You may get yourself a lower rate.

Either way, talk to your loan officer. With mortgage rates still near historical lows, homeowners have interesting options. Just don't wait too long. LIBOR -- and mortgage rates in general -- are known to change quickly.

Your ARM Is Adjusting Lower. Is There A Downside To Letting It?

When adjustable-rate mortgages are on the verge of adjusting, a common concern among homeowners is that their mortgage rates will adjust higher.

Well, this year, because of the math of how ARMs adjust, homeowners around the country are seeing that mortgage rates on ARMs can sometimes adjust lower, too.

Adjusting conforming mortgages are adjusting to as low as 3 percent.

As a quick review, here's the timeline for most conforming adjustable-rate mortgages:

1. There's a "starter period" in which the interest rate remains fixed. This can range from 1-10 years.
2. There's a rate change after the starter period. It's called the "first adjustment".
3. Subsequent, annual adjustments follow until the loan "ends". This is usually after Year 30.

The adjustments each year are based on a math formula that's included in the contract with your lender. It's surprisingly basic.  Each year, your new, adjusted mortgage rate is equal to the sum of some constant -- usually 2.25 percent -- and some variable.  The variable is most commonly equal to the 12-month LIBOR.

As a formula, the math looks like this:

(Adjusted Mortgage Rates) = (12-Month LIBOR) + (2.250 Percent)

LIBOR is an acronym standing for London Interbank Offered Rate. It's an interest rate at which banks borrow money from each other -- very similar to our Fed Funds Rate here in the United States. And also like our Fed Funds Rate, LIBOR has been low lately.

As a result, adjusting mortgage rates have been low, too.

In 2009, 5-year ARMs adjusted to 6 percent or higher. Today, ARMs are adjusting to 3.000%.

Based on the math, you may want to let your ARM adjust with the market year. Or, if you plan to keep your home long-term and have concerns about adjustments in 2011 and beyond, it may be a good time to open a new ARM.  The same forces that are driving down LIBOR and helping to keep mortgage rates low overall, too.

Consider talking to your loan officer and making a plan. With mortgage rates as low as they've been in history, most homeowners have options.  Just don't wait too long. LIBOR — and mortgage rates in general — are known to change quickly.