Getting a mortgage while self-employed
Would it be worth legitimizing his business or is it too late at this point? To be blunt, you're asking if we recommend that he stop breaking the law. The answer is obviously yes, he should be declaring his income. And it would probably benefit him to get on the same page as his employer (or client) so they can both start obeying the law together. Once he's filed a tax return for 2016 that would certainly help his cause as far as a lender is concerned, and  as soon as he can provide some recent pay stubs (or paid invoices) he should be ready to move forward on the mortgage based on that additional income.
What options do I have? Realistically?  Get a regular full time job.  Work at it for a year or so and then see about buying a house. That said, I recently purchased a decent home.  I am self-employed and my income is highly erratic.  Due to how my clients pay me, my business might go a couple months with absolutely no deposits.   However, I've been at this for quite a few years.  So, even though my business income is erratic, I pay myself regularly once a month.  In order to close the deal with the mortgage company I had to provide 5 years worth of statements on my business AND my personal bank accounts.  Also I had about a 30% down payment.   This gave the bank enough info to realize that I could absolutely make the payments and we closed the deal. I'd say that if you have little to no actual financial history, don't have a solid personal income and don't have much of a down payment then you probably have no business buying a house at this point.  The first time something goes wrong (water heater, ac, etc) you'll be in a world of trouble. During World War II, the United States (US) instituted wage and price controls.  To attract better employees, companies would offer benefits to get around salary limits.  Health insurance was one of the more successful benefits.   At that time, income taxes were newer and there were many ways to evade them.  Companies could generally deduct expenses.  So at that time, health care was deductible because everything was.  And at that time, only wages were taxable compensation from employer to employee.   Since that time, many other benefits have become non-deductible for employers, e.g. housing or the reduced deduction for meals and entertainment.  But health care is generally regarded as different, as a necessity.  While everyone needs to eat, not everyone needs to eat at a $100 a meal restaurant.  People who need expensive health care really need it.  People who eat expensive food just prefer it.   And of course, health care is more intermittent where food is relatively consistent.  You don't need ten thousand calories one day and zero the next.  But some families have no health care expenses in a year while another might have cancer or a pregnancy.  Note that medical care expenses can be deducted for individuals if they are large enough in aggregate and you itemize.   And of course both businesses and workers have incentives to maintain the current system with deductibility.  Health insurance is a common benefit.  Housing is not (although it's worth noting that travel housing and meals are deductible).  So there have been few people impacted by making housing taxable while many people would be impacted by taxable health insurance.   You can deduct health insurance costs if self-employed.  It's also not true that health insurance is the only benefit with preferential tax treatment.  Retirement and child care are also deductible.  Even meals and housing can be deducted in certain circumstances.  The complex rules about what and how much is deductible.   There have been rumbles about normalizing the tax treatment of health insurance and medical care, but there is a lot of opposition.  Insurance companies oppose making all healthcare expenses deductible, as that reduces their effective benefit.  They would prefer only insurance premiums be deductible.  Traditionally employed individuals oppose making health insurance taxable, as that would increase their taxes.  So the situation persists.  There isn't quite enough support to move in either direction, although the current compromise is economically silly. You will need to register as self-employed aka sole trader (that's the whole point: pay taxes on income that you're not getting as wages from an employer, who would arrange PAYE/NI contributions), or set up a limited company (in the last case you would have the option of either getting paid as wages or as dividends — which one is better is a complex issue which varies from year to year). You'll find lots of advice on the HMRC website. When you do your tax return, your total income from the year from all sources is added up. So you will need to include your employment income as well as your contractor income. Any tax taken off at source through PAYE will then be deducted from how there is to pay. So whether you pay the tax or your employer pays it, it should end up the same, although the timing will differ. There will be differences in National Insurance treatment, and you don't necessarily have a free option to choose which happens - the nature of your relationship may mean you have to be classed as either employed or self-employed under HMRC rules. What is the question? Are you just trying to confirm that for self-employed, a Solo 401(k) is flexible, and a great tool to level out your tax rates? Sure. A W2 employee can turn on and off his 401(k) deduction any time, and bump the holding on each check as high as 75% in some cases. So in a tight stretch, I'd save to the match, but later on, top off the maximum for the year. To the points you listed - Your observation is interesting, but a bit long for what you seem to be asking. Keep in mind, there are 2 great features that you don't mention - a Roth Solo 401(k) flavor which offers even more flexibility for variable income, and loan provisions, up to $50,000 available to borrow from the account. My fellow blogger The Financial Buff offered an article Solo 401k Providers and Their Scope of Services that did a great job addressing this. People typically present themselves to be as wealthy as possible to banks and as poor as possible to the government at tax time.  Gross income is really the most reliable number for most folks. Your and your employer are required by law to report an accurate gross income figure annually. Anything else is totally situational.  All they are doing anyway is computing your total debt-to-income ratio and mortgage-to-income ratio. The government agencies that buy mortgages, the big bank that buys the mortgage or the self-underwriting bank has differing standards for different products. There are certain situations where you could legally pay yourself rent, but it'd be in the context of multiple business entities interacting, never in the context of an individual renting their own property.  Even if you could, any rent paid to yourself would count as rental income, so there'd be no benefit. Edit: I was hunting for examples where it might be acceptable, and didn't, but I found a good explanation as to why it is not acceptable from Brandon Hall on a BiggerPockets post: To get technical, you will be going up against the Economic Substance   Doctrine which states that a transaction has economic substance if:   (1) the transaction changes in a meaningful way (apart from Federal   income tax effects) the taxpayer’s economic position; and (2) the   taxpayer has a substantial purpose (apart from Federal income tax   effects) for entering into such transaction. By transferring your primary residence into a LLC, you would not be   changing your economic position. Further, you do not have a   substantial purpose for entering into such transaction other than to   simply avoid paying federal income taxes. So it might make sense if multiple people owned the LLC that owned the property you wanted to rent, and there are instances where company X owns holding company Y that owns an office building that company X rents space in. But if you're the sole player in the LLC's then it sounds like a no-go. "Your plan as proposed will not work, because it goes against how banks make money. Banks make money in two ways:  (1) Fees [including account fees, investment advice fees, mortgage application fees, etc.]; and (2) Interest Rate Spread. They borrow money for x%, and they lend it out for x+y%. In a simple form, someone gives the bank a deposit, and earns 1%. The bank turns around to the next person in line and loans the money to them for 4%. You are asking them to turn the interest rate spread into a cost instead of their main source of profit: You are asking the bank to borrow money from another person paying them 1.2% interest, and then loan the money to you, paying you 0.6% interest and keeping 0.6% for themselves. The bank would lose money doing this. Technically yes, you can borrow from a bank and invest it in something earning above the 4% interest they will charge you. You can then pay the bank's interest off of your earnings, and make some profit for yourself. BUT this carries an inherent risk: If your investment loses money, you still owe the bank, effectively increasing the negative impact of your investment. This tactic is called ""Leveraging""; you can look it up on this site or on google. It is not something you should do if you do not fully understand the risks you are taking on. Given that you are asking this question, I would suggest tactfully that you are not yet well informed enough to make this sort of investment. You run serious risk of losing everything if you over-leverage (assuming the banks will even lend you money in the first place)."