Deductions and Write-Offs

Interest earned on U.S. Treasury bonds is fully taxable for Federal purposes and reportable on IRS Schedule B, but not subject to state or local income taxes.

Generally There is no federal tax due on interest on bonds from states, cities, counties, possessions of the U.S. or the District of Columbia.
Generally, these same items have to be added back as income on the state return subject to state tax.

Original Issue Discount (OID) occurs when a long-term debt instrument is issued at a price that is lower than its stated redemption value. OID is the difference between the stated redemption price at maturity and the issue price of a debt instrument.
OID interest usually is found in debt instruments of bonds or notes. Generally, a 1099-OID slip is issued with the taxable amount included.
OID interest is reportable on IRS Schedule B. There are certain exceptions to the OID requirements, as well as situations when the OID slip may be ignored.
Speak to your local CPA or check IRS publication 1212 about the reporting of the 1099-OID on your tax return.

Interest earned on zero coupon bonds is treated as original issue discount (OID) and is taxed every year owned.
You will receive a 1099-OID slip reporting the taxable amount that is reportable on IRS Schedule B.

No. There are 2 limitations that come in play. The deductible amount taken as an entertainment expense for tickets is the face value of the tickets. The excess amount paid to a ticket agent or scalper is not deductible. Secondly, all meals and entertainment expenses are limited to 50% of the cost. The deduction will be claimed on the business Schedule C Form or Form 2106. You should maintain a diary of all business expenses listing the person, the event, the date and the business agenda that was discussed.

Generally yes. If you refinance the same amount of your old mortgage existing balance with a new mortgage, then the mortgage interest is fully deductible.
If you refinance your home mortgage for more than the existing balance, then the deductibility depends on the amount financed and the use of the funds.
If the excess funds are used to build, buy or substantially improve your first or second home, then it is considered a Home Acquisition debt.
If the excess is used for other purposes, such as paying off credit card debt, for a car loan or paying for your child's education, then it is considered Home Equity debt.
There is a $100,000 (50,000 for MFS)maximum Home Equity debt interest allowed limitation and a 1 million (500,000 MFS) maximum Home Acquisition debt interest allowed limitation. The deduction will be claimed as a Schedule A mortgage interest itemized deduction.
The total itemized deductions claimed may also be limited based on your Adjusted Gross Income. Points paid on a refinance are amortized over the life of the new mortgage. Speak to your local CPA about the deductibility of the refinanced mortgage interest.

The amount may be either fully, partially, or non-deductible.
The margin account investment interest expense is limited to the amount of net investment income, plus any elected amount of net capital gains from the sale of investment property such as stocks or mutual funds.
Generally, investment income is gross income from property held for investment, such as interest, ordinary dividends, royalties, or annuities. Limited investment interest in excess of investment income not deducted in the current year may be carried over to future years.
It is not lost. The deductible amount is figured on IRS Form 4952. Speak to your local CPA for the deductibility and possible elected amount of the net capital gain from investment property.

Interest on loans to buy tax-exempt securities are not deductible.

No. Pre-paid business or investment interest must be amortized over the life of the loan. It may not be deducted in full in the year pre-paid.