Q: My son received a stimulus payment of $300. He paid his Social Security tax in 2007, but had a big loss in his business and received a large reimbursement of his estimated tax payments to the IRS. He was surprised not to get [a] $600 stimulus check. The purpose of the law was to get money into the hands of people, but my son seems to have been denied the $600 because of the tax refund based on a net loss in self-employment. This doesn’t seem right. …

— E.M., East Providence

A: I assume that your son is single and has no children. For someone in such circumstances, the minimum federal economic stimulus payment — also known as a rebate — is generally $300; the maximum is generally $600.

So why did your son receive only the minimum rebate amount? Keep in mind that the Internal Revenue Service calculates your rebate amount based on the information provided on the federal income-tax return you filed earlier this year, the one covering 2007, said Mary F. Bernard, former president of the Rhode Island Society of Certified Public Accountants.

A key factor in that calculation is your “net tax liability” for rebate purposes. Ask your son to dig out a copy of his U.S. Form 1040. His net tax liability for rebate purposes is on Line 57. Here’s how the rule applies in his situation:

•If his net tax liability was greater than $600, he generally would have received the maximum rebate of $600.

•If his net tax liability was between $300 and $600, his rebate generally would have been equal to that “in between” amount.

•If his net tax liability was less than $300, he would have received the minimum rebate of $300.

“You would only get $600 if you had enough [of a net] tax liability,” said Bernard, who is tax principal at Kahn Litwin Renza & Co., Ltd., a CPA firm in Providence.

Your son should have received — or will soon receive — a notice from the IRS explaining how his particular rebate amount was determined.

Q: I got an explanation in the mail that my husband and I are only entitled to a combined [rebate] of $600, and I am a little confused. I have twin boys in college and I have twin children who are 17 so I know that we’re not eligible for the children. But what I am not sure about [is] why my husband and I are not each getting $600. …

— S.I., Cranston

A: For a married couple who filed a joint federal income-tax return earlier this year, the minimum overall rebate amount is generally $600; the maximum is generally $1,200.

(You’re also generally allowed an additional rebate amount of $300 for each child you have who was under 17 as of Dec. 31, 2007. But as you noted in your question to MoneyLine, you don’t qualify based on your children’s ages.)

So why did you get the minimum? It probably has to do with your net tax liability, as mentioned above.

For rebate purposes, find your net tax liability on Line 57 of your Form 1040, or Line 35 of your Form 1040A:

•If the amount is greater than $1,200, you would have received the maximum rebate of $1,200.

•If the amount is between $600 and $1,200, your rebate would have been equal to that “in between” amount.

•If the amount is less than $600, you would have received the minimum rebate of $600.

So chances are you received a $600 rebate because your net tax liability was $600 or less, said IRS spokeswoman Peggy Riley.

There are other possible reasons, too. For example, your rebate can be reduced if you are delinquent on federal income taxes, state income taxes, child-support payments or federally backed student loans.

In addition, your rebate amount can be reduced (possibly to zero) if your adjusted gross income exceeds a certain threshold — $150,000 if you’re married and filed a joint return, $75,000 if you’re single. (Adjusted gross income is a figure found on the front of your return, toward the bottom.)

Q: My question is on the rebate stimulus package. … I never noticed anything about people that had to pay [the] IRS this year. Are they still entitled to get [a] rebate? And when will those checks be mailed out? … I owed about $400 and paid it in March this year. …

— B.L., Dayville, Conn.

A: “Rebates are not dependent on whether you got a refund or had a balance due” on your federal income-tax return this year, Bernard said.

So if your 2007 return showed a balance due, you’ll still be eligible for a rebate. How much of a rebate depends mainly on the amount of your net income tax liability, as described above.

When will you receive your rebate? Please keep these points in mind:

•The Treasury can’t issue a rebate until it processes your return.

If you filed early enough in the season for your return to be processed by April 15, your rebate will be included in the first batches to be distributed by the Treasury.

•The Treasury in late April began distributing the first batches of rebates. That process will continue through mid-July.

As a general rule, if you filled out the “direct deposit” section on your return, the Treasury will deposit your rebate directly into your bank or credit union account. If you didn’t fill out that section, you’ll receive a rebate check in the mail. (Directly deposited rebates are generally issued earlier than paper checks.)

•The distribution takes time. For example, with last week’s round, the Treasury has now distributed more than half of all the rebates scheduled to be issued this year. So although many rebates have been issued, many have yet to go out.

•If you filed your return later in the season — anywhere from about mid-March to mid-April — chances are the IRS didn’t get to process it by the April 15 deadline. As a result, your rebate won’t be part of the first batches; it will go out later, perhaps late next month or some time in August.

In general, it takes six to eight weeks — maybe longer — to process a return. Once processing is complete, you should receive your rebate “shortly after that,” Riley said.

Q: My question is regarding my son. He and his wife separated last year. They both had to file married …separately, with different addresses. My son is concerned that the $600 check that each of them is supposed to get will go to his former home address instead of the address he is living at now, which is on his income tax return. Need that be a concern, or will he get his own check? Again, they filed separately … with different addresses. Will they each get their own separate check?

— P.C., Portsmouth

A: The IRS will process each rebate based on the information listed on each return, Riley said.

As a result, the Treasury should issue a rebate to your son, based on the address of record as listed on his return, Riley said.

Similarly, the Treasury should issue a separate rebate to your son’s wife, based on the address listed on her return, Riley said.

(This assumes that each is eligible for a rebate. For instance, it assumes that each has a net tax liability, as described above. It also assumes that neither one is delinquent on federal income taxes, state income taxes, child-support payments or federally backed student loans, and that each of them has a valid Social Security number.)

To be absolutely sure that the rebate goes to the correct address, your son may want to consider filing Form 8822, “Change of Address,” with the IRS, and a change-of-address notice with the United States Postal Service, Riley said.

For a copy of Form 8822, visit your local IRS office, call the IRS toll-free at 1-800-829-3676 to have a copy mailed to you at no charge, or download a copy from this IRS Web site:

www.irs.gov/formspubs

Change-of-address information is available at your local post office, and on the Postal Service’s Web site:

www.usps.com

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