Exotic mortgages are receiving triple-A ratings. Former Goldman Sachs bankers are swarming the nexus of government and economics. Share prices for bank stocks are surging. Markets are pricing in a series of interest rate hikes. Stock valuations are nosebleed high. Drill, baby, drill. Is it late 2016 or early 2008?

It took the United States roughly half a century to forget some of the lessons of the Great Depression, and when we did, we got the banking crises of the 1980s. With the election of Donald Trump, the U.S. now appears ready to beat that record by about four decades. In a new bout of willful forgetting, America is on the verge of reverting to the kinds of policies that prevailed before — and brought on — the financial meltdown of 2008 and the Great Recession.

First, the facts. Surprising almost everybody, the stock market has roared ever higher since billionaire businessman Trump won the presidency on Nov. 8. The S&P 500 stock index is up more than 6 percent, climbing to new record highs led by leaps in bank stocks and energy companies.

Another crisis isn’t imminent; by all accounts the U.S. economy looks quite healthy. Unemployment has fallen from a high of 10 percent in October 2009 to 4.6 percent in November. The economy has created new jobs for a record 74 consecutive months. Inflation and interest rates remain low. Corporate profits are relatively high.

Nevertheless, the economic-policy turn expected under Trump could well create some costly messes to clean up sooner rather than later.

Why? The prospect of deregulation.

Trump is expected to loosen the rules governing fossil fuel production, offshore drilling, and exploration on federal lands and the Arctic. Relaxing EPA fuel efficiency regulations would boost gasoline sales over time. The agglomeration of oil and gas industry titans in Trump’s cabinet – most notably Trump’s pick for secretary of state, ExxonMobil CEO Rex Tillerson, and for energy secretary, former Texas Gov. Rick Perry – has energy shares screaming higher (the recent rebound of oil prices has also helped push those stocks up).

Shares of financial institutions are rising on expectations that Trump will fulfill campaign promises to “dismantle” the sweeping 2010 Dodd-Frank Act, which overhauled regulation of a U.S. financial system that had essentially melted down.

Regulation adds costs, at the margin, which have made it less profitable to run giant oil companies and banks in recent years. But lack of regulation also has costs. And when bankers run amok, those costs are almost always borne by the public, at least at first.

During the worst of the Great Recession, American taxpayers were put on the hook for more than $1 trillion in loans to shore up the banking system, as well as hundreds of billions of dollars in ownership stakes in large banks and other institutions. Almost all of it was paid back once the economy stabilized.

But that doesn’t account for the damage done to the economy as a result of the recession, which has been estimated at anywhere from $6 trillion to $14 trillion, according to an analysis from the Federal Reserve Bank of Dallas.

Shareholders should also note that industries gone wild can have huge negative implications for them. The 2010 Deepwater Horizon spill in the Gulf of Mexico ended up costing BP roughly $62 billion, according to the oil giant’s final estimate.