Comcast, which owns CNBC parent NBCUniversal, said it would pay 100,000 frontline and non-executive employees special $1,000 bonuses. The company also said it is making the move because of the FCC's recent change in broadband rules and tax reform. It also said it plans to spend well in excess of $50 billion over the next five years on infrastructure improvements.

Both Fifth Third Bancorp and Wells Fargo followed, saying they would raise their minimum wage to $15 an hour. Fifth Third said it would also give workers a bonus, and Wells Fargo said it would give $400 million to community and nonprofit organizations next year.

In the hours after Congress approved the GOP tax cut plan, a handful of companies jumped to announce plans to share some of the proceeds on their employees and spend on infrastructure. Boeing was first out of the gate, followed by AT&T , which said it would give more than 200,000 unionized employees a special bonus of $1,000 once the tax bill is signed. The company also said it would increase its capital expenditures by $1 billion.

Expect a stampede of companies handing out bonuses, raising pay, spending on capital projects and giving to charities, with the windfall from the massive corporate tax cuts passed Wednesday.

"This is exciting stuff. This is good. This is not just a whole bunch of guys saying I can buy back a lot of stock here and jazz up my numbers through financial engineering. This is a bunch of business leaders saying we can use this tax benefit to grow our company, keep our loyal employees and assist the community," said Dick Bove, banking analyst at Vertical Group.

The corporate tax rate is being cut to 21 percent from 35 percent. Bove said banks pay an average 31 percent tax rate.

Bove said he now expects the other banks to follow with similar announcements.

"It looks like they are going to use that money to stimulate more employee loyalty by increasing spending. They are also going to get more liberal with their stock programs. They are going to increase philanthropic activity because it's one of the ways they stimulate business," he said. "I was convinced they were going to cut prices and go to war with each other, which I'm sure they will still do."

Boeing also announced $300 million in employee-related spending and charitable donations. FedEx, when it announced earnings, said it expects U.S. GDP could increase materially next year as a result of tax reform. It said it would likely then increase its capital expenditures and hire to accommodate the additional volumes triggered by higher growth.

The announcements were met by some cynicism by Wall Streeters, especially since the Justice Department has sued to block AT&T's acquisition of Time Warner. Time Warner stock ended the day higher, after AT&T made the announcement, and President Donald Trump praised the company's action during a celebratory event with Republican members of congress.

But overall, the announcements were seen as positive steps for companies that are not only seeing the tax rate fall but benefiting from important changes in how they account for capital spending.

Yet companies have also been spending on stock buybacks — with $86 billion announced so far this month, the most since June, according to Trim Tabs. Democrats have said the bill favors only business and the rich, and Senate minority leader Chuck Schumer's office circulated a list of companies that announced buybacks.

Schumer criticized the AT&T announcement, and said the company paid a low tax rate over the last decade. "They have 80,000 fewer employees today than they had then," he said.

Also, companies raising minimum wage may be forced to do so anyway. There are 18 states and some cities where the minimum wage was going to rise in 2018. New York City will have a rate of $15 an hour.

But Bove said the fact companies have immediately given money to workers is a positive surprise, and it could boost the economy if enough do it.

"You'll see more companies doing this," said Quincy Krosby, chief market strategist at Prudential Financial. "It's excellent PR after all the mantra across the aisle that it's just a tax plan for the rich and for corporate America and for people who own stocks. ... It's a good PR move, giving back to the folks in the company."

"It affects the psychology of the moment. Giving back to your workers. This was a major victory for corporate America," she said of the tax cuts.

She also expects to see more banks making announcements since they are a major beneficiary of not only the tax cuts, but also deregulation.

"It's good PR. It's good corporate citizenship," said Jack Ablin, CIO of BMO Private Bank. "It's Christmastime. It's the holidays. It's spreading the good cheer around. It's probably from a communications and PR perspective smart, and probably proactive because they're going to get pressure. They might as well do it ahead of time."

Ablin said companies will feel pressured if their competitors make announcements on pay and bonuses.

The industries that see the biggest advantage in the tax law are expected to spread some of the proceeds around. Industrial companies are among the winners, as are media and retailers.

Tech is the sector that will gain the least from tax reform, since the average tax rate is about 24 percent.

"It would be smart for utilities to say they're going to cut their rates because regulators will probably force them to do it anyway," said Ablin.

Disclosure: Comcast is the parent company of NBCUniversal, which owns CNBC.

Correction: This report has been updated that show that Boeing was the first company to announce new employee-related spending in response to the new tax law.