Based on feedback from our readers, it seems the only thing most borrowers understand about Private Mortgage Insurance (PMI) is that without it, many of them would be denied mortgages. While for many borrowers, this is indeed the case, it’s important to be aware of the other options that exist.

First, let’s start with the basics: what is PMI? As implied by the name, PMI is literally an insurance policy on your mortgage, which protects the lender in case of default. Typically, PMI is required on mortgages with a loan-to-value of greater than 80% (i.e. when the down-payment is less than 20% of the value of the mortgage). The insurance is calculated as a percentage of the the total mortgage value, and is rolled into the monthly mortgage payment.

PMI is not cheap, and will average about $1,000 per year on a $200,000 mortgage. Generally speaking, insurance premiums for fixed-rate mortgages are lower than for variable-rate mortgages. In addition, long mortgage durations (30 years, as opposed to 15 years), and high loan-to-value mortgages are associated with higher PMI premiums. This is to be expected, since mortgages with these characteristics typically have higher default rates.

One alternative to making monthly PMI payments is to roll a one-time premium into the mortgage. Thanks to current tax rules (mortgage interest is tax-deductible, while PMI premiums are not), it will be cost-effective for the average borrower to do so. Unfortunately, most borrowers are not aware of this possibility, because lenders require special authorization to process it and hence avoid mentioning it to prospective borrowers. Finally, while such a strategy will technically raise the size of your mortgage, some (or even most) of this premium will be rebated to you when it is determined that you no longer need it.

Speaking of which, mortgage insurance is only a temporary outlay. After your loan-to-value ratio exceeds 80%, you will no longer be required to pay for it. This is natural, since if your loan-to-value ratio had been this high when you first obtained the mortgage, you wouldn’t have been required to purchase PMI.  In fact, thanks to a law passed in 1999, lenders must take the initiative to cancel the mortgage insurance agreement when the LTV falls below 78%, based on the initial appraised value of the home. Borrowers are also entitled to early cancellation (though, you must request it), if your equity exceeds 25%, based on a current appraisal of the home.

As I mentioned, private mortgage insurance is quite expensive, and hence not-at-all desirable. This is because the mortgage insurer is selected by the lender – not by the borrower – which doesn’t have as much of an incentive to cut costs. Accordingly, it might be economical to pay a higher interest rate in lieu of PMI, if your lender offers you such an option. The best approach is to simply (save up until you can afford to) make a higher down-payment, such that PMI is no longer necessary.

In the wake of the credit crisis, a wave of consolidation in the mortgage lending industry has left only a handful of large firms standing. As a result, Wells Fargo, Bank of America and J.P. Morgan Chase collectively dominate mortgage lending, accounting for half of all new loans. Wary of both the structural risks and obstacle to competition that this represents, Fannie Mae is moving to provide a leg up to small, community-based lenders.

Towards that end, Fannie will effectively guarantee all-short term debt issued by such lending institutions, provided that funds received from such debt issuance is used to originate new mortgages that meet Fannie’s lending standards. It should be noted that in most cases, Fannie Mae (and/or its counterpart, Freddie Mac) already guarantee the majority of the mortgages issued by such lenders. While this protects the mortgages that the lenders originate, it doesn’t protect the lenders themselves. Thus, this program, will make it easier for small lenders to raise capital to fund mortgage-origination activities by guaranteeing their solvency.

The upshot is that this should not only increase overall mortgage lending activity, but also enable smaller lenders to compete more effectively more with the big boys. Previously, small lenders were hoarding existing capital and having trouble raising new capital, since investors were rightfully worried about the viability of the loans that they were making. For better or worse, this initiative means that they should be able to offer new mortgages at lower rates and less rigid lending standards.

Certainly, this program is not without its critics. The WSJ has suggested tongue-in-cheek that the government should just go ahead and nationalize the entire mortgage lending industry given that it is now directly responsible for ensuring its functioning. “Fannie and Freddie’s guarantees and subsidies helped to create the housing disaster, which has led the Fed directly to purchase mortgage-backed securities and mess up the market for small mortgage lenders, which in turn is leading Fan and Fred to guarantee the debt of those small lenders,” summarized its editorial board.

For those of you contemplating a mortgage, this means that you can obtain one from a small lender, without worrying about whether it will still be in business tomorrow. There’s no longer a substantial advantage associated with taking out a mortgage from a “Big-Box” lender, since smaller lenders can now compete on terms and pricing. In fact, given the bureaucracy of large lenders, it might be smoother to simply work with a regional/community lender, with which it will be easier to work with in the event of a problem.

Determining the size of one’s down-payment is more complicated than it would seem. Historically, the prevailing wisdom regarding down-payments was the larger the better. During the inflating of the housing bubble, however, this logic was turned on its head, and it was even possible to take out a no-money down mortgage. As it turns out, there are advantages and disadvantages to both approaches.

Personal finance columnists usually advise a down-payment of 20% Loan-to-Value (LTV). In other words, take the size of your mortgage, multiple it by 20%, and VOILA, you have your down-payment. According to their reasoning, 20% is substantial enough both to demonstrate your creditworthiness to the lender and to cushion you from negative price swings in the value of your home.

Given the decline in housing prices, however, it’s perfectly conceivable that borrowers that made 20% down-payments are still underwater in their mortgages. After a foreclosure, then, such borrowers will be left with stains on their respective credit report, and gaping holes in their personal assets. From the lender’s perspective, meanwhile, such borrowers are actually considered less credit-worthy than those that make the minimum required down-payment. For those of you scratching your heads: It turns out that those who make down-payments between 20-25% are actually more likely to default. In addition, such borrowers aren’t required to purchase private mortgage insurance, further increasing the cost of default to the lender.

The cost of private insurance, then, can actually be recouped in the form of lower interest rates! In other words, there isn’t much of a financial penalty (sometimes even a reward!) for making a smaller down-payment. Some financial planners now encourage making the smallest allowable down-payment, based on the reasoning that borrowers can then set aside extra money in an emergency fund, making it less likely that they will become delinquent (miss payments) on their mortgage further down the road.

What is the minimum down-payment? Well, that depends on the loan, and the lender. A Federal Housing Administration (FHA) loan requires a 3.5% down-payment. [However, proposed legislation would increase this to 5%]. For veterans, or those that live in rural areas, there are VA home loans and Guaranteed Rural Development loans, respectively.

For those not eligible for the loans above, it might be worth looking into a down-payment assistance program. Some of these programs are also government sponsored, and/or provide low-interest loans to be used exclusively for making a down-payment. There are also several not-for-profit companies which offer down-payment assistance, typically by rolling the down-payment into the overall loan amount, but such organizations have come under scrutiny in the wake of the collapse of the housing market. For first time home-buyers, the $8,000 tax credit can now be “monetized” and applied towards the down-payment. [Under earlier rules, the credit was received in the form of a tax credit, and hence, could not used for a down-payment.]

For those still struggling to scrape together the cash, there are a few more options available to you. First, you can talk to your lender and try to pledge securities in lieu of making a down-payment, but be advised that such is tantamount to borrowing money to buy stock. Second, if you already own the land that your home is (being) built on, that may qualify as a down-payment. Third, you can appeal to family/friends for help, but be aware that the lender will demand proof that any such assistance is a gift, rather than a loan. Finally, you might try talking to the seller, and asking him to help you make your down payment (offset in the form of a higher sale price). This will only be possible, however, if the sale price initially exceeded the appraised value.

All else being equal, a larger down-payment should translate into smaller monthly payments, as a result of both lower principal and interest. It should also lower your mortgage insurance premiums. As I noted above, however, some lenders actually penalize those who make larger down-payments. Ultimately, every situation is different, and it probably makes sense to use a mortgage calculator to crunch the numbers associated with a few different scenarios to see ultimately which one makes the most (financial) sense for you.