What diversification actually protects you against

There are really two kinds of risk in investing. One is market-wide risk, sometimes called systematic risk, the kind that comes from things like recessions, interest rate changes, or a global crisis, which drags down almost everything at once. No amount of spreading your money out removes this risk, because it touches the whole market.

The other kind is company-specific or sector-specific risk, sometimes called unsystematic risk. This is the risk that one company gets caught in a scandal, one industry gets disrupted, or one property loses value because of something local to it. This is the risk diversification actually protects you against, by making sure no single company, sector, or asset can sink your entire portfolio on its own.

That distinction matters because it sets realistic expectations from the start. A diversified portfolio will still fall when the whole market falls, that's normal and expected, but it won't be wiped out because one company you were overly exposed to went bankrupt. This course builds up, piece by piece, everything that goes into constructing that kind of portfolio on purpose rather than by accident.

Someone puts their entire ₱200,000 in savings into a single company's stock. When that company gets hit with a fraud investigation, the stock drops 60%, wiping out ₱120,000. Someone else spreads ₱200,000 across 30 companies in different industries. When one of those 30 companies has the same scandal, it drags their overall portfolio down by less than 2%, because that one company was never more than a small slice of the whole.