If you claim a tentative refund based on the carryback of an unused general business credit, attach a detailed computation showing how you figured the credit carryback and a recomputation of the credit after you apply the carryback. For 2010, an unused eligible small business credit (ESBC) can be carried back 5 years. Generally, an unused general business credit, that is not a 2010 ESBC, must be carried back 1 year.

However, the new hire retention credit (Form 5884-B) cannot be carried back to a tax year before March 18, 2010. Also, unless you are an eligible small business, the credit for small employer health insurance premiums generally cannot be carried back before 2010.

For an ESBC, make the recomputation by including the carryback first in line 10 of the 2006 Form 6478, Credit for Alcohol Used as a Fuel. Any such credit not used in 2006 must be carried to 2007 (the next earliest carryback year), and so on, by including any remaining unused ESBC on the following forms.

For any general business credit other than an ESBC, make the recomputation on the 2010 Form 3800.

ESBCs are the total of the general business credits (other than the new hire retention credit and the employer housing credit) determined in 2010 for an eligible small business. An eligible small business is a corporation the stock of which is not publicly traded, a partnership, or a sole proprietorship, if its average annual gross receipts for the 3-tax-year period before 2010 is not more than $50,000,000. For additional rules and details, see the Instructions for Form 3800.

If you filed a joint return (or separate return) for some but not all of the tax years involved in figuring the unused credit carryback, special rules apply to figuring the carryback. See the instructions for Form 3800.

An individual can elect to carry back a net section 1256 contracts loss to each of the 3 tax years preceding the loss year. An estate or trust is not eligible to make this election. To make the election, check box D at the top of Form 6781. The amount which can be used in any prior tax year cannot exceed the net section 1256 contract gain in that year and cannot increase or create an NOL for that year. Reflect the carryback as a reduction to your adjusted gross income in the “After carryback” column on line 11. Attach to Form 1045 a copy of Form 6781 and Schedule D (Form 1040) for the year of the net section 1256 contracts loss and an amended Form 6781 and an amended Schedule D (Form 1040) for each carryback year. For more details, see section 1212(c).

If an NOL or net section 1256 contracts loss carryback eliminates or reduces a prior year foreign tax credit, you cannot use Form 1045 to carry the released foreign tax credits to earlier years. Also, if the released foreign tax credits result in the release of general business credits, you cannot use Form 1045 to carry the released general business credits to earlier years. Instead, you must file Form 1040X or other amended return to claim refunds for those years. For details, see Rev. Rul. 82-154, 1982-2 C.B. 394.

Use one pair of columns to enter amounts before and after carryback for each year to which the loss or credit is being carried. Start with the earliest carryback year. A net section 1256 contracts loss can be carried back 3 years. See the instructions for line 10 that begin on this page to figure the tax years to which you can carry an NOL. Use the remaining pairs of columns for each consecutive preceding tax year until the loss is fully absorbed. Enter the ordinal number of years the loss is being carried back and the date the carryback year ends in the spaces provided in the headings above line 10 for each pair of columns.

For each carryback year, enter in the column labeled “Before carryback” the amounts for the carryback year as shown on your original or amended return. If the amounts were previously adjusted by you or the IRS, enter the amounts after adjustment.

Use the following rules to figure the tax years to which you must carry an NOL shown on Schedule A, line 25. If an NOL is not fully absorbed in a year to which it is carried, complete Schedule B to figure the amount to carry to the next carryback year.

Enter in the column labeled “Before carryback” your adjusted gross income (AGI) for the carryback year as shown on your original or amended return.

Enter in the column labeled “After carryback” your AGI refigured after you apply the NOL or net section 1256 contracts loss carryback and after you refigure any items of income and deductions that are based on or limited to a percentage of your AGI. Amounts to refigure include:

Use your refigured taxable income (Form 1045, line 15, using the “After carryback” column) to refigure your tax for each carryback year. Include any tax from Form 4970, Tax on Accumulation Distribution of Trusts, and Form 4972, Tax on Lump-Sum Distributions. Attach any schedule used to figure your tax or an explanation of the method used to figure the tax and, if necessary, a detailed computation.

For example, write “Tax Computation Worksheet–2009” if this is the method used for that year. You do not need to attach a detailed computation of the tax in this case.

The carryback of an NOL or net section 1256 contracts loss may affect or cause you to owe alternative minimum tax. Individuals use Form 6251 to figure this tax. Estates and trusts use Schedule I (Form 1041).

The 90% limit on the alternative tax net operating loss deduction (ATNOLD) does not apply to the portion of an ATNOLD attributable to qualified disaster losses, qualified GO Zone losses, or qualified disaster recovery assistance losses. Instead, the ATNOLD for the tax year is limited to the sum of:

Enter in the column labeled “After carryback” for each affected carryback year the total of the recomputed general business credits, using Form 3800 (or using Forms 3800, 5884, 6478, 8586, 8835 (Part II), 8844,or 8846, if applicable, to recompute the general business credits for years before 2008).

If an NOL or net section 1256 contracts loss carryback eliminates or reduces a general business credit in an earlier year, you may be able to carry back the released credit 1 year. See section 39 and the instructions for Form 3800 for more details on general business credit carrybacks.

See your tax return for the carryback year for any additional credits such as the earned income credit, credit for child and dependent care expenses, child tax credit, education credits, foreign tax credit, retirement savings contributions credit, etc., that will apply in that year. If you make an entry on this line, identify the credit(s) claimed.

Do not adjust self-employment tax because of any carryback.

See your tax return for the carryback year for any other taxes not mentioned above, such as recapture taxes, tax on an IRA, etc., that will apply in that year. If you make an entry on this line, identify the taxes that apply.

If you apply for a tentative refund based on an overpayment of tax under section 1341(b)(1), enter it on this line. Also, attach a computation showing the information required by Regulations section 5.6411-1(d).