The stock market has had an ugly last few months.

Through the close on Monday, stocks were down 20% from their late-September highs. Wednesday’s historic rally that saw the Dow log its largest single-day point gain on record while the S&P 500 had its biggest one-day increase since 2009 will alleviate only some of the recent market stress.

Recent weeks have seen a torrent of explanations trying to peg the sell-off on one cause — Trump’s tweets, the trade war, the Fed, the global economy, and so on. None of these takes, however, really satisfies an investor that is still looking at a market down 15% this quarter, with some of the worst trading action since the financial crisis and some of the weakest price action in the market’s history.

A recent note out of Nomura’s global markets team led by Kevin Gaynor caught our eye on Wednesday, as it outlines some of the biggest changes in corporate, government, and household behavior since the financial crisis.

The short of it is that corporate America has done almost all of the levering up in the post-crisis period, putting non-financial corporate debt near record highs as a percent of U.S. GDP. And a lot of that risk has been taken on in the private market, not the banking sector, making companies — and by extension their stock prices — more exposed to market gyrations than in previous cycles.

“Corporates have taken advantage of a slow household debt build-up to substantially increasing gross issuance via markets rather than the banking sector,” the firm writes. “As a result, they are more exposed to market conditions than ever before – the banking sector may be safer, but asset holders will be more exposed to corporate credit than ever before. How this affects the dynamics of a deleveraging is uncertain, but ‘fire sale’ risk must have increased.”

The following two charts from Nomura show both the run-up in corporate debt compared to GDP and the shift of corporate debt out of the banking sector and into private markets.

The increase in corporate indebtedness — with so much of this debt taken on via sales to the private market rather than loans from banks — should at least in part help explain why stresses we’ve seen in the stock market are so acute relative to what economic data would suggest about the likelihood of an economic downturn.

A company that has depended on secondary market financing for operations now faces significantly less friendly market conditions. Last week, Reuters reported that corporate debt sales were tracking at their lowest level since 2011. More challenging market conditions are thus exacerbated by market-dependent borrowers.