Tetris finance. In the computer game Tetris, it's a good thing to collapse a column. In finance, it's not. There were warnings (as early as 2004) about yields not fully pricing in risk, but with the stock market setting records, the warnings fell on deaf ears. Then the Federal Reserve began hiking interest rates as the economy seemed poised to send inflation higher - belatedly, according to some. That exposed adjustable mortgage rates. That set off problems in the housing market.