Held to maturity isn't safety — it's a bet depositors won't leave.银行把债券记成“持有到期”，并不等于高收益率带来的亏损消失——它只是把这笔亏损押在“储户不会提前走”这一个假设上。

A bank booking its bonds that way doesn't make the loss from higher yields disappear; it just parks that loss on one assumption: that depositors never leave.

The 10-year US Treasury yield posted its sharpest rise since 1994 this quarter. Bank of America's unrealized losses on its bond holdings reached about $109 billion by the end of September, up from $85 billion at the end of June; the industry's unrealized losses ran to about $326.7 billion in the second quarter. Those numbers aren't the risk themselves. As long as yields stay high, 'held to maturity means no loss' only pays off if depositors never leave, the one variable a bank can't control.

So the real choice today isn't up or down; it's sell or hold. Sell, and you crystallize the loss and cut into capital. Hold, and the paper loss freezes that capital in place, quietly dragging on lending and buybacks; Fifth Third has delayed repurchases, and Wells Fargo has tied future buybacks to rates. SVB wasn't killed by the paper loss; it died when the deposits left first.

Today's paper loss is only about a third of the 2023 round — roughly 5% of bank capital, versus 19% then — and deposits have grown for eight straight quarters, so the buffer is thicker. But its 'safety' is written in depositor behavior, not in the bank's own ledger.

What would change this view? If the 10-year yield falls back, industry unrealized losses shrink, and deposits keep growing, the fragility thesis weakens.

Research, not investment advice.