The timing is very hard to pick."This is the idea that the US government is not currently in a position, or lacks the fiscal firepower, to rescue big Wall Street banks at present if they do run into financial trouble.Indeed, the weaker US bond market has been something of an alarm bell in this regard in recent months.The US 10-year Treasury bond yield was trading at a two-year high of 4.6 per cent earlier this year Any yield approaching 5 per cent for the 10-year bond is considered alarming.Bond yields rise when bonds are sold off because investors demand compensation for the higher risk of default.Donald Trump said the bond market got "yippy" — jittery — when he announced his so-called reciprocal tariffs in April 2025.Rising yields or interest rates can be devastating for stock valuations.But there is another potential cause for concern.The moral hazard behind the big stock market gains is pushing many firms into indexes that are followed by managed funds.Once they're in the index, fund managers who follow the index buy them up.You can see how this could feed on itself.Conversely, Dale warns, if an economic shock hits the market that removes several big companies from any index, that is when you might see a share market collapse."If people start to withdraw at some point, then you get the alternative spiral," she said."It goes the other way, so this idea that we can never see a meaningful downturn, I think, is risky."But we've all been wrong about that for quite a while."And many of our superannuation balances are showing the spoils of this.