Loading up on passive income stocks is a great way to ride out a bear market. Reliable cash distributions are a proven way to minimize losses, and elite dividend stocks tend to be among the first to recover following marketwide downturns. 

Which top-tier passive income stocks should investors consider buying right now? Amgen (AMGN -0.71%) and Bristol Myers Squibb (BMY -0.18%) are two blue chip biopharmaceutical companies with ample free cash flow and a strong track record of raising their dividends on a regular basis. Here's why investors may want to add these two names to their portfolios soon.

A blue sticky note with dividends written on it and a roll of 100-dollar bills next to a calculator.

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Amgen: A proven winner

Amgen's shares have risen by a stately 30.6% so far this year. As a result, the biotech's stock price is currently bumping up against its 52-week highs at the time of this writing. For context, the S&P 500 has fallen by 20.3% this year, while the Nasdaq Composite has sunk by an eye-catching 32.9% in 2022. The biotech's shares are thus trouncing the broader markets this year. 

Amgen's stock has been able to defy this brutal bear market because the company is in the business of selling essential, life-saving medicines. So, even though falling sales of legacy products like the white blood cell booster Neulasta have weighed on its top line of late, Amgen is still generating enormous free cash flow on a quarterly and an annual basis. Speaking to this point, the biotech posted a whopping $2.8 billion in free cash flow in the third quarter of 2022.

What does all this mean? Amgen's stock is an ultra-safe passive income vehicle. The company's hefty free cash flow easily cover its annualized dividend yield of 2.88%, evinced by its fairly average trailing-12-month payout ratio of 62.9% (roughly average for a big pharma stock). What's more, management has proven its commitment toward rewarding shareholders by boosting the company's dividend yield by a staggering 1,257% over the past 10 years. All told, Amgen's recession-proof business, stellar free cash flow, and rock solid dividend program make it an excellent stock to own during a bear market.  

Bristol: A de-risked turnaround story

Bristol's stock was stuck in a rut to start the year. Investors were avoiding the big pharma early on in the year over concerns that it wouldn't be able to overcome a slew of patent expires. Recently, Bristol lost exclusivity for the cancer drugs Abraxane and Revlimid. And in the back half of the decade, the company is staring down patent expires for both Opdivo and Eliquis -- two of the pharma giant's best-selling medications right now. 

By scoring a series of high-value regulatory wins for drugs like Camzyos, Opdualag, and Sotyktu, however, Bristol's stock has been able to find its proverbial feet and even go on to post a market-beating gain of nearly 30% so far this year.

Part of Bristol's appeal to investors is its strong free-cash-flow generation. The company's diverse product portfolio, consisting of numerous essential medicines, is expected to produce $45 billion to $50 billion in free cash flow over the period covering 2022 to 2024.

The net result is that Bristol's dividend program is on solid financial ground. Underscoring this point, the company's forward-looking payout ratio ought to drop to below 70% by the end of next year, which will put it roughly in line with the industry average for this key financial metric. Now, Bristol's annualized dividend yield of 2.7% won't exactly turn heads on Wall Street. But the company's quarterly distribution is a safe bet, which counts for a lot in an era characterized by uncertainty and risk.