Even if your overall cash-flow situation is good, but you still need to cover a short-term deficit, today’s still-strict credit environment often won’t allow you to take out a loan.  More than likely, your only option would be an untapped home equity line of credit or a generous relative.  If that’s the case, great.  If not, you may be able to turn to a surprising source for some help: the taxman.

If you’re self-employed, an investor or someone who lives off Social Security benefits, pension payments, retirement account withdrawals, and the like, you can apply for loan from the Internal Revenue Service.  Better yet: To borrow from the IRS, you don’t have to fill out any annoying applications, prove your income or fence with a balky loan officer.  While this may sound too good to be true, it is true.

What you do is simply postpone some federal income tax payments that you would otherwise make to the IRS via estimated tax installments.  You don’t need the government’s permission.  You just do it and then make up the difference later.  Of course, the IRS will charge interest on the difference between what you should have paid in for each installment and what you actually paid.  However, the current interest rate on estimated tax underpayments is only 3%.  While the rate can potentially change each quarter, it will probably remain at a reasonable level for a while.

The IRS calls the interest on estimated tax underpayments a “penalty.”  But since the current interest rate is only 3%, it’s not really a penalty.  In fact it’s actually a pretty good deal for someone with a short-term cash crisis.

Note: If you are a salaried employee, you must pay in federal income taxes via payroll withholding.  You may be able to adjust the withholding downward a bit for the rest of this year by turning in a revised Form W-4 to your employer.  However, the strategy of borrowing from the IRS is basically unavailable to you.  Sorry.

Estimated Taxes:

There is no federal income tax withholding on income from self-employment activities conducted via sole proprietorships, partnerships, or LLCs.  Nor is there generally any required federal income tax withholding on interest income, dividends, capital gains, Social Security benefits, pension payments, or taxable retirement account withdrawals.  Instead those with income from these sources are expected to make four installment payments of estimated taxes for each year. The installments for the 2012 tax year are due on Apr. 17, June 15 and Sept. 17 of this year, and Jan. 15 of 2013.  Obviously the first date has since passed, but the next three are still in the future.  So you can work with the installments due on those dates by paying in less than you owe or even nothing at all.

As mentioned, you will be charged interest based on the difference between the amount you should have paid in for each installment and the amount you actually pay for as long as the underpayment remains outstanding.  The amount that you should pay in for each installment generally equals the lesser of: (1) 22.5% of what you expect to report on your 2012 Form 1040 for total federal income and self-employment taxes or (2) 25% of what you reported on your 2011 return (27.5% if your 2011 adjusted gross income was over $150,000).

Borrowing from the IRS in this fashion is only a short-term fix.  By no later than April 15th of next year, you must catch up for any estimated tax payment shortfalls for the 2012 tax year.  If you don’t, the IRS will start charging additional interest of half a percent per month on the shortfall, which equates to a 6% annual rate.  That 6% is on top of the “regular” interest charge, which is currently only 3%.  So you could be looking at a rate of 9% or maybe more.  In any case, owing the IRS for 2012 taxes after April 15th of next year is just not a good position to be in.  So, if you are not ready, willing, and able to pay up by that date, this is not a good option for you.  You do not, however have to wait until April 15th to catch up.  You can do so as soon as you are able and that is the recommendation.

It’s no secret that women live longer than men.  But a new study by the Wharton School’s Retirement Research Center suggests that some professional financial advisers neglect to take that fact into account when they tell clients how to time their Social Security benefits.

The mistake could cost women who outlive their husbands, and who might benefit from a significant monthly check into their 80s or 90s.  Slightly more than half of women 65 and older rely on Social Security for three-quarters of their income, according to the Employee Benefits Research Institute. Choosing when to start taking benefits—a decision that can be affected by factors like health, savings and other sources of income is complex even for pros.

While seniors can start receiving checks as early as age 62, doing so means they’ll get less each month than they would if they waited until the maximum age of 70 to start taking distributions.  Spouses that don’t work, usually women, in the baby boomer generation currently reaching retirement age—also receive benefits based on their partners’ earnings.

But women’s longevity is not being taken into account in the calculus, the study found.  “At age 62, there’s a lot you can do,” says co-author Andrew Biggs, a former Social Security Administration official.  “You may have a big 401(k), you can go still go back to work.  At 72, there are a lot fewer options.”

The study, which posed questions about a number of specific scenarios to a group of about 400 professional financial advisers, suggests that many are tailoring their advice to the needs of the husband without thinking as carefully about the impact on the wife.

For instance, presented with a 62-year-old man in average health who wants to retire right away but has, together with his wife, saved $800,000, only one in five advisers suggested he put off taking Social Security as long as possible.  The recommendations were made despite the fact that with such a large nest egg, the couple appeared to face little immediate need for cash and the decision would significantly crimp the woman’s survivor benefit should she become a widow.

Of course, while most financial advisers are men, the study doesn’t prove that these conclusions were driven purely by chauvinism.  A more charitable explanation might be that the advisers perceived the chief breadwinner in each scenario as their client.

Another, says Biggs, is that the educational materials provided by the government, while recently improved, haven’t historically done a good enough job of emphasizing the issue.