High conviction. That's what you want to have with the stocks you buy. Such stocks are ones that you can be enthusiastic about -- and buy heavily.

We asked three Motley Fool contributors to identify stocks for which they have high convictions about buying right now. Here's why they think that AbbVie (ABBV -0.76%), Exelixis (EXEL 0.78%), and Vertex Pharmaceuticals (VRTX 1.36%) are stocks to buy hand over fist in December.

A Dividend King with better prospects than many think

Prosper Junior Bakiny (AbbVie): The end of the year is always a great time to review your investment portfolio. Those who hold shares of AbbVie may be considering jumping ship before 2023 comes around. The drugmaker is set to lose U.S. patent protection for its biggest cash cow -- autoimmune-disease medicine Humira -- next year. Patent cliffs are never good for drugmakers, especially when it affects a therapy that has been as successful as Humira. 

But this obstacle won't doom AbbVie's prospects, not by a long shot. The company has built a lineup of solid products to take over as Humira's sales start fading. AbbVie's portfolio now includes immunosuppressants Skyrizi and Rinvoq, its Botox franchise, cancer medicine Venclexta, schizophrenia treatment Vraylar, and more. AbbVie's Skyrizi and Rinvoq look particularly promising. Both are raking up approvals across many of Humira's indications.

Management even thinks they could combine to eclipse Humira's peak sales. And beyond the company's current portfolio, it boasts a rich pipeline with dozens of active programs. Expect more new approvals and label expansions with AbbVie, allowing it to deliver solid financial results year after year. AbbVie's solid business constitutes one reason to buy its shares, but the drugmaker is also worth considering for its dividend. 

AbbVie is a member of the very elite group of Dividend Kings, having raised its payouts for 50 consecutive years. The pharma giant currently offers a dividend yield of 3.74%, a solid cash payout ratio of about 45%, and the prospects of more payout increases given its storied dividend history and robust business. 

It is clear that AbbVie has a lot more going for it than just its blockbuster medicine Humira. As the year draws to a close, it remains an excellent stock to buy despite the loss of U.S. exclusivity it will experience next year.

A bargain biotech stock with strong financials

David Jagielski (Exelixis): Shares of biotech company Exelixis are down 9% this year, and that's a buying opportunity for investors. The company has solid financials, a great product in Cabometyx, and plenty of cash on its books. That puts the business in excellent shape to continue growing and expanding.

What separates the growth stock from many others in biotech is that it already has some fantastic fundamentals behind it. Exelixis has reported profits of $307.6 million over the trailing 12 months on revenue of $1.6 billion, which makes for a profit margin of 19%. That's impressive for a growing company that has loads of potential.

The business is also growing at an impressive pace. In its third-quarter earnings (period ended Sept. 30), Exelixis reported sales of $411.7 million, up 25% year over year largely due to the continued growth of its kidney cancer drug Cabometyx. This drug generated $361.4 million in revenue, increasing by 39% from the prior-year period.

Some investors may be concerned about the company's long-term growth. But Exelixis is evaluating XL092 in late-stage testing as a potential treatment for metastatic colorectal cancer. The company also isn't done with Cabometyx as it has other trials featuring the drug in an effort to expand its label. Exelixis is sitting on $2.1 billion in cash as well, which could help it pursue other growth opportunities.

Trading at only 11 times its future profits (based on analyst expectations), Exelixis looks to be a bargain buy right now. Investing in the stock today could prove to be a smart move.

An unstoppable growth stock

Keith Speights (Vertex Pharmaceuticals): I think that Vertex Pharmaceuticals is a practically unstoppable growth stock. And it's not just because the biotech's shares have soared in 2022.

Vertex continues to enjoy a monopoly in treating the underlying cause of cystic fibrosis (CF). It still has plenty of growth opportunities in the CF market. More importantly, though, Vertex is branching out beyond CF.

The company and its partner, CRISPR Therapeutics, could have the first CRISPR gene-editing therapy on the market next year with exa-cel. Vertex is already gearing up for the commercial launch of the sickle-cell disease and transfusion-dependent beta-thalessemia drug pending regulatory approvals. It's also laying the groundwork for the potential launch of another drug in the near future -- non-opioid acute pain therapy VX-548.

Vertex's pipeline features two other late-stage candidates. The combination of vanzacaftor, tezacaftor, and deutivacaftor just might be the company's most powerful CF drug yet. Inaxaplin could be on the way to becoming the first drug approved to treat APOL1-mediated kidney disease.

All of these programs have blockbuster sales potential. In addition, Vertex is evaluating a potential cure for type 1 diabetes in early-stage clinical studies. 

You'd think that a stock with such tremendous prospects would be ridiculously expensive. That's not the case with Vertex. Shares currently trade at a price-to-earnings-to-growth (PEG) ratio of only 0.41. Any level below 1 is considered to be attractively valued.