Some of the world's largest biopharmaceutical companies are making moves to buy back stock in the year ahead, together racking up more than $38 billion in repurchase plans announced since December 2017.

That compares with overall new biopharma buybacks of about $14 billion at the beginning of 2017, though some drugmakers expanded on existing programs and others ramped up spending throughout the year. Early in 2017 Pfizer Inc., AbbVie Inc. and Novartis AG each tacked $5 billion onto existing programs, which for AbbVie brought its total target up to $19 billion at that time.

The recent spate of repurchasing plans follows three straight years of gradual increases in share buyback expenditure, led mostly by the healthcare and financial sectors in the wake of recovery from the Great Recession, according to analysis in 2017 by Howard Silverblatt, senior index analyst for S&P Dow Jones Indices.

Several of the companies now repurchasing their stock are recently flush with cash following the U.S. tax reform law passed Dec. 20, 2017. Besides lowering corporate tax rates, it forced U.S. companies to bring overseas cash back onshore, albeit at a lower rate than usual.

American drugmakers were some of the biggest overseas hoarders, coming in behind only the technology sector in 2016, according to an S&P Global Ratings report in 2017.

Many of those same companies assured investors and analysts that their cash influx would go to research and development, possible deals and definite shareholder returns in the year ahead.

AbbVie's $10 billion of repurchases follow $5.3 billion lodged in full-year 2017 profits alongside higher sales expectations for 2018.

Analysts and investors openly wondered during the company's latest earnings call whether solid profits and fresh onshore cash could spur a deal. Yet while Chairman and CEO Rick Gonzalez acknowledged that it was a cash-rich company, he said the late-stage pipeline looked promising enough for at least the next five years.

"As we look at capital deployment, I can tell you, our philosophy is always that the first priority for us is continuing to invest back in the business in order to make sure that we can drive long-term sustainable top-tier growth," Gonzalez said.

Gonzalez then shed some light on the buyback and dividend plan that they subsequently put to the board in February, saying that the company knew ahead of tax reform that they would put potential cash toward shareholder returns in a mix of higher dividends and buybacks.

Celgene Corp. — which saw shares dip late last year in the wake of a late-stage drug failure — followed a roughly $3 billion fourth-quarter share buyback with $5 billion more announced this February, bringing it to a total $30.5 billion in repurchases over the last nine years.

"Our stock was really in a different spot during the fourth quarter, so we saw it as a great opportunity," Peter Kellogg, executive vice president, CFO and chief accounting officer, said on the earnings call. "I wouldn't assume that every quarter, you're going to see us clicking off the exact same amount of share repurchases."

Celgene is one of the few companies that has already channeled some of its repatriated cash to dealmaking, announcing the $9 billion purchase of cancer drug developer Juno Therapeutics Inc. in January.

"We're not trying to plug any holes the next few years at all," Kellogg said as he discussed future capital deployment plans.

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