Some estimates suggest that more than 1 million Americans who purchased a home last year are eligible to deduct their upfront mortgage points, even if the seller paid them.

Q: I purchased a home last year, and the seller paid the $3,200 in upfront points that the bank required before providing me with a 30-year mortgage. A friend says that I can deduct the points, even though the seller paid them. Is this true?

A: Yes, it’s true. It’s hard to believe, but the Internal Revenue Service allows buyers to take a deduction for any points that the seller pays.

There’s no solid estimate of how many of last year’s buyers will benefit from this tax loophole when they file their returns that are due next month. But some analysts speculate that more than 1 million Americans may be eligible for the handsome but often-overlooked write-off, in part because many sellers last year began offering to pay part of their buyers’ closing costs as the real estate market softened around summertime.

As usual, the ability to take the deduction comes with some strings attached. First, you can’t claim the write-off if you choose to take the standard deduction instead of itemizing your return.

The other catch is that if you’re a buyer who takes a deduction for seller-paid points, the “tax basis” of your home automatically will be lowered by an equal amount. This means that your net profit that’s subject to taxation will be a few thousand dollars higher when you sell.

But that probably won’t matter, because the IRS allows most single tax-filers to keep the first $250,000 in profit tax-free and allows married sellers to keep up to $500,000 away from taxation.

Consult a tax professional for details. If you’re eligible to deduct the seller-paid points, claim the cost on Line 12 of your Schedule A tax form or – if the points were reported to you via a Form 1098 from the bank – on line 10 of Schedule A.

Q: How can I contact the National Association of Realtors?

A: The trade group that represents more than 1 million realty agents is headquartered at 430 N. Michigan Ave., Chicago, IL 60611. Its toll-free phone number is (800) 874-6500. The association also has a terrific Internet site, at www.realtor.org.

Q: Every now and then, you answer some off-the-wall real estate questions. So, here’s mine: In the TV show “Gilligan’s Island,” did any of the characters ever say where the island was located?

A: Although the opening theme song explained that the seven castaways were supposedly shipwrecked on an “uncharted desert isle,” a handful of references the characters made over the mere three years (1964-67) the sitcom aired on network TV suggested that the island was about 300 miles southeast of Hawaii.

In reality, the first episode was filmed in Hawaii, and the rest were shot mostly in a relatively small building in the Los Angeles suburb of Studio City – the same sound stage that was later used to tape “The Mary Tyler Moore Show” and “Roseanne.”