Cash Flow & Safety Net
What you can genuinely afford to invest, and the two things that must be settled before you invest anything at all.
- 01Only your monthly surplus can be invested. Your salary is not the number that matters.
- 02Hold three to six months of essential spending in cash before buying anything.
- 03Debt above roughly 7% a year beats every return this site can find, guaranteed.
What you can actually invest
1.1Cash flow is the only number that matters
Cash flow is money in, money out, and what is left. Most people can state their salary instantly and have no idea what survives the month. The survivor is the only money that can ever become an investment.
1.2Why the surplus beats the salary
Someone earning €2,000 a month with €300 left over is in a stronger position than someone earning €6,000 with nothing left over. The second looks wealthier and is one missed payslip from selling assets at whatever price the market offers that week.
Work out your surplus before you look at a single ticker. If it is negative, closing that gap is worth more than any investment decision you could make this year.
The safety net, and the order of operations
1.3The buffer exists so you are never a forced seller
Hold three to six months of essential spending in cash — instant access, not invested. Closer to six if your income is irregular or you are the only earner.
The buffer is not really about emergencies. Markets fall hardest when the economy is weak, which is precisely when people lose work. Without a buffer, a job loss forces a sale at the bottom, converting a temporary paper loss into a permanent one. The buffer is what buys you the right to wait.
1.4Expensive debt outranks every investment here
Clearing a credit card at 22% returns 22% — guaranteed, immediate, tax-free, risk-free. A broad equity index has historically returned somewhere around 7–10% a year before inflation, and delivers it unevenly: up 25% one year, down 30% the next. The comparison is not close.
1.5What counts as investable capital
A useful test is to follow the cash: an asset puts money into your pocket each month; a liability takes money out. Not what it is worth — which direction the money moves.
The home you live in fails that test. Mortgage, insurance, repairs and property tax all flow out, and nothing flows back. Rent the same property to someone else for more than it costs and it becomes an asset. The building did not change; the direction did. This is why home equity is not investable capital, however large it is on paper.
An accountant would define an asset differently — anything you own with value, your home included. Both definitions are correct; they answer different questions. The cash-flow test asks "what is paying me?", which is the more useful question when deciding what to buy next.
Your investable capital is savings, less a three-month buffer, less any expensive debt. It is almost always a smaller number than people expect, and using the honest one is what keeps a bad year survivable.
You now have one figure: the amount you could put at risk without damage if it went to zero. Enter it as your account size and the position sizer will handle the arithmetic from there.
Stock Analysis → Risk Settings