No. Allowing joint tax returns raises the taxable income for the purpose of tax increase structure. An individual making $150,000 a year is taxed at a different rate than an individual making $200,000 a year. A married couple where one makes $150,000 and one making $50,000 a year will each pay taxes at a lower rate than one person making $250,000 a year. Join them and tax the whole at the higher rate. It's called the marriage penalty.
The Tax Act passed in January made the marriage penalty relief provisions permanent for all taxpayers with incomes under $250,000. In practice this means that most married couples with incomes under that amount pay the same whether they file jointly or separately. Standard professional grade software automatically calculates the difference and in 95%+ of the returns in our practice the difference is under $25.
The only significant tax avoidance reason for filing separately is when one spouse has a smaller amount of income (and therefore is in a lower bracket), and major deductions limited by a percentage of AGI (medical expenses, casualty losses, and certain miscellaneous itemized deductions, primarily business and investment expenses).
But most people don't realize that the finances actually have to be kept separate, this includes separate bank accounts, separate checks to pay the household bills. Separate contributions for major purchases. Failure to keep adequate records could subject a married couple to income tax evasion and perjury charges as they might have filed taxes separately, but the money was always commingled.
I think you are over the top here. Businesses (including Schedule C's are required to maintain sufficient books and records to substantiate their income and expenses. Individuals must maintain sufficient records to document any deduction, loss, credit, or other tax-favored treatment they claim. There is no overall requirement to keep any other records. The normal consequence of not keeping records is to allow the IRS to use "indirect" methods of reconstructing income and to disallow favored tax benefits.
Conmingling monies makes proof harder, but there is no requirement that business finances be kept separate from personal, nor that taxpayers filing jointly maintain separate records.
Perjury and presenting the IRS with alter or forged documents is certainly a no-no. But failure to keep adequate records, no matter how egregious, will only subject a taxpayer to a Code Section 6662 (a) or (b) penalty (20% or 40% of the understated tax). Tax crimes bearing the possibility of jail time require overt acts and a high standard of proof.
There are two relief provisions that generate a lot of business for us. "Injured spouse relief" allows a taxpayer on a joint return to receive a refund based on a "shadow return" of what items of income, deductions, and witholdings are attributable to them when their spouse is subject to a refund intercept program. "Innocent spouse relief" mitigates the joint liability principle when it would be inequitable to hold the spouse responsible on a joint return for erroneous items of the other spouse.
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