The Tax Cuts and Jobs Act, passed on a party line vote in the Senate and signed into law last December, cut the corporate tax rate from 35 percent to 21 percent and allowed for full expensing of investments in business equipment.

In the ensuing months, many prominent firms announced one-time bonuses, increases in pay for lower-wage hourly workers, increases in 401(k) matches, and additional discretionary contributions to defined benefit plans.

According to the White House's Council of Economic Advisers, almost 500 firms had announced bonuses or pay increases by April 8, affecting more than 5.5 million workers.

Other companies announced increased matches to 401(k) plans.

“We've seen client companies take advantage of the new tax law by providing employees with increased retirement benefits,” said Michael Knowling, Prudential Retirement's head of client relations in a statement.

Cigna, the fifth largest health insurance payer in the country by revenue that covers 15 million subscribers, announced a permanent increase in its company match by 1 percent for its 30,000 employees. Cigna sold its retirement business to Prudential in 2003. Prudential Retirement is the record keeper for Cigna's $5 billion 401(k) plan.

“The net financial benefits of U.S. tax reform are an opportunity for us to continue to demonstrate our commitment to our employees.” said John Murabito, Cigna's executive vice president for human resources, in a statement.

All of the companies surveyed by Prudential also sponsor defined benefit pension plan for either current or former employees. Three-quarters of surveyed executives said they are likely to make “substantial” contributions to DB plans by September 15, the final date at which contributions can be deducted at the previous 35 percent tax rate.

Eight in 10 executives said they expect the increases in wages and benefits to improve productivity and positively impact company bottom lines.

Critics of the TCJA have argued the lower corporate tax rate will mostly result in stock buybacks and higher dividend payments to shareholders, and not increased wages and benefits to rank-and-file employees.

Four in 10 Respondents in Prudential's survey said they plan to do both as a result of the tax cuts, to the benefit of investors—among them those employees that own company stock in 401(k) plans.

Cigna's common stock accounts for 14 percent of assets in its 401(k) plan, according to Brightscope. The company has not announced a share buyback, but is currently exploring a merger with pharmacy benefits manager Express Scripts. A proposed merger with Anthem was blocked by the Department of Justice last year.

In the first quarter, $242.1 billion in share repurchases by public companies were announced, a record at the time that did not stand for long. The second quarter saw another $433.6 billion in share repurchases. Goldman Sachs is predicting share repurchases could hit $1 trillion for 2018.

Most of the finance executives surveyed by Prudential also expect accelerated capital investment as a result of the TCJA, potentially spurring further economic growth—and potentially further increases in wages, notes the report.

Increases in wages and benefits are expected to translate to improved worker financial wellness, the study says.

But how much of an improvement in aggregate financial wellness will not be calculable immediately. “Measurable movement on these metrics will require the passage of time,” the report says.