The Federal Reserve will lend $2.3 trillion to support the economy, including loans to businesses and backstops for corporate borrowing. Even with that much money to spend, the Fed won’t touch some formerly hot areas of the markets.

The Fed excluded some securities tied to corporate loans and commercial real estate that were among the newest, fastest-growing segments of the bond markets. Optimistic outlooks and rosy credit ratings made them popular among investors searching for high yields on supposedly safe securities.

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