Because in this case it’s a bank and they aren’t selling equity to invest in new business/products.

SVB had to liquidate good assets quickly, so it sold them at a loss. That means its capitalization compared to liabilities (deposits) could be in “uh oh” territory.

So it sells capital on the open market to shore up its liquid capital. Yes, most every capital raise works mostly like this. But it’s notable here because of what it portends.

> For what reason besides raising cash does a company ever sell shares in itself?

A healthy company doesn't generally sell shares in itself (except perhaps to fund a major expansion). Selling equity is a last resort when you don't have better funding options (retained earnings, debt, ...).