US drugmaker Pfizer, which has been considering a split into two companies for more than two years, said it will not do so because the move would not create any shareholder value.
Pfizer said it will keep its low-growth generics and patent-protected branded medicines separate.
This will give it the option to split down the road if "factors materially change at some point in the future."
Pfizer said today the decision would not have an impact on its 2016 financial forecast.
The decision not to create two publicly traded companies follows the collapse of its planned $160 billion acquisition of Allergan after a change in tax law took away the tax benefits of the deal.
Investors were expecting the company to step back from the split, analysts said.
The pharma giant began openly planning for the possible split in early 2014, saying it would operate the businesses as separate divisions and track their progress for three years before reaching a decision.
In August, it said a decision would be made by the end of the year.
Pfizer said the sum-of-the-parts analysis showed no benefit to shareholders, and that tax costs and business disruptions were factors it considered.
The company had considered the move largely because its patent-protected medicines routinely enjoy sales growth while sales in the generics portfolio usually declined.
Investors shifted their focus to whether Pfizer would split after the company terminated the deal for Irish drugmaker Allergan in April.
In August Pfizer announced it was buying cancer drugmaker Medivation for $14 billion to get access to blockbuster prostate cancer drug Xtandi for its growing oncology roster.
The Medivation deal illustrates a shift in Pfizer's mergers and acquisitions strategy from lowering taxes, which was the rationale behind the failed Allergan tax inversion deal, to strengthening its lineup of branded drugs, especially lucrative cancer treatments.
A year ago, Pfizer paid $15 billion for Hospira, which sells generic hospital products and is developing biosimilars to compete with big-selling injectable biotech drugs.
That deal was seen by Wall Street as a way of bolstering its generic drugs operation ahead of potentially divesting the business.