There’s blood on the Street.

In a wild swing of the ax that has shocked many pundits, Wall Street’s biggest banks have slashed nearly 50,000 jobs, and bonuses and expense money are being cut as profit opportunities dry up.

And there’s no easy way out, analysts say, because the Fed’s quantitative easing that once rescued the financial system with trillions of cheap dollars is — at least for now — history.

But while some analysts were unnerved by the carnage announced by banks last week during their earnings calls, the warning signs were there before — from lower trading and commodities revenues to currency risks and long-term interest rates that have trended lower.

The fourth quarter saw thousands more workers fired. Total reductions for 2014 were about 20,000 at Brian Moynihan’s Bank of America; 10,000 at Citigroup led by Michael Corbat; and 10,000 at Jaime Dimon’s JP Morgan. Morgan Stanley reports on Tuesday.

Many job losses were already flagged — attributed, for example, to a decline in servicing of delinquent loans as banks cleared troubled mortgages. But analysts also see brutal cost-cutting.

“Look, I think head count in the banking industry is likely to decline,” said CLSA investment group bank analyst Mike Mayo. “And if this environment remains, headcount would get significantly reduced.”

By Mayo’s calculations, bank revenues are the weakest in eight decades, a shocking throwback to the Great Depression.

And the carnage is ongoing as global growth slows and commodity prices and currency movement roil the markets.

“I think there have been heavy potential and paper losses at this point. Clearly, nobody bet properly on oil — nobody thought it was going to be below 50 a barrel,” said Tim Quast, president of market analytics firm ModernIR.

Even mighty Goldman Sachs didn’t escape last week’s destruction. Although the firm reported fourth-quarter earnings a tad better than forecast on Friday, that came from painful expense-shearing as revenues, hurt by a plunge in bond trading, posted a nauseating double-digit decline. Declines in bond activity also rocked JPMorgan, Citigroup and Bank of America.