That is when BioNTech BNTX, -5.54% and Pfizer Inc.’s PFE, -1.71% COVID-19 vaccine was waved through to start distribution in the U.S., while a shot developed by Moderna Inc. MRNA, -8.98% is quickly becoming a second option as the nation races to gain control of the pandemic.

Here’s a chart showing the top 40 most actively traded U.S. corporate bonds since the vaccine rollout.

The broad rally, led by bank debt, comes after shares of financial companies were pummeled in 2020, with investors initially shunning segments of the economy viewed as vulnerable to the pandemic’s shocks and its aftermath.

Banks not only hold consumer deposits, but they also make real-estate loans and arrange financing, mergers, acquisitions and equity deals for major U.S. corporations, or a direct link to the health of the economy.

In a hopeful sign this fall, debt investors started to change their tune, at least when making shorter-term bets on major banks.

See: Debt buyers are betting on big banks — over the short term, at least

BondCliQ data for December shows the rally in bank debt now has expanded to bonds due in 10 years and beyond, indicating that investors have become more hopeful that a successful vaccination program will help drive economic recovery and reduce credit losses.

“Banks were as much in the crosshairs during the initial stage of the COVID outbreak as anything,” Brian Levitt, Invesco’s global market strategist, told MarketWatch, adding that the big fear in any recession is that stress will find its way into the banking system.

But those concerns subsided after the Federal Reserve stepped in with a raft of emergency lending facilities, including buying up corporate debt for the first time ever this spring.

Read: Here’s how a dispute over the Fed’s emergency powers almost sank the stimulus package

Now there’s optimism around the vaccine rollout helping to spur further economic recovery in 2021, Levitt said, adding that the expectation is that the 10 year U.S. Treasury yield TMUBMUSD10Y, 0.921% also will likely move higher, helping banks which lend based on the benchmark.

“That type of environment favors cyclical assets, and that’s largely the banks,” he said.

Bank shares closed lower Tuesday, but rallied to kick off Christmas week, after the Fed on Friday gave lenders the green light to start buying back stock again in 2021, a reversal of restrictions put in place in June amid concerns about the COVID-19 pandemic.

The Dow Jones Industrial Average DJIA, -0.67% fell 200 points Tuesday, pressured lower by concerns about a new strain of the coronavirus in the U.K. that curbed travel from the nation to swaths of the globe.

Bank bonds issued by Morgan Stanley MS, -1.75%, Wells Fargo & Co. WFC, -2.00% and Goldman Sachs Group Inc. GS, -2.68% also were among the top 10 most actively traded debt since Dec. 11.

Bucking the broader rally was debt issued by a handful of companies, including Verizon Communications Inc. VZ, -0.84%, Ford Motor Co. F, -1.57% and Apple Inc. AAPL, +2.85%.