You don't have to be in a hurry when it comes to buying stocks. At least that's true most of the time. Whether you invest sooner or later usually doesn't matter all that much over the long run.

However, there are some examples where a sense of urgency could be appropriate to some extent. Here are three top stocks to buy hand over fist before the end of 2022 (listed in alphabetical order).

1. Eli Lilly

Eli Lilly (LLY -1.22%) should have plenty of good news on the way next year. We can start with the continued rapid sales growth for Mounjaro in treating type 2 diabetes. The drug raked in a whopping $203 million in its first two quarters on the market, including $86 million from a sales collaboration agreement. 

Mounjaro could have an even bigger market opportunity in treating obesity. Lilly's rolling submission to the U.S. Food and Drug Administration (FDA) will primarily include data from two clinical studies, one of which should wrap up in April 2023. Analysts project that Mounjaro will reach peak annual sales of $15 billion and perhaps much more.

The FDA could grant accelerated approval to donamemab in treating Alzheimer's disease early next year. However, the Centers for Medicare and Medicaid Services (CMS) would limit coverage of the drug to clinical trials only, even if it wins accelerated approval. The bigger story for Lilly will come in mid-2023 with the results from its late-stage study of the Alzheimer's disease drug.

In addition, Lilly hopes to win U.S. and European approvals for lebrikizumab in treating atopic dermatitis next year. The drug could generate peak annual sales in the ballpark of $1.5 billion. 

Maybe you could wait to buy this big pharma stock. However, Lilly's potential is already creating enthusiasm among investors, with shares soaring more than 30% this year. Holding off too long could cost you.

2. Novocure

I view Novocure (NVCR -0.20%) as one of the top stocks to buy in December. Why? The clock is ticking until the company reports important clinical results for its tumor treating fields (TTFields) therapy.

Novocure plans to announce the results from its late-stage study of TTFields in treating non-small cell lung cancer (NSCLC) in early 2023. The therapy has already won regulatory approvals in multiple countries as a treatment for glioblastoma. It's also picked up FDA approval in treating mesothelioma. I predict positive news in the NSCLC indication.

This is a big deal because NSCLC has a much larger patient population than glioblastoma and mesothelioma combined. Sure, it will take Novocure a while to win regulatory approval and market TTFields in the new indication. However, the company's prospects could improve dramatically in just a few weeks.

Novocure has more potential catalysts on the way as well. The company expects to report data from its late-stage study of TTFields in treating recurrent ovarian cancer next year. In 2024, Novocure should announce results from phase 3 studies targeting brain metastases and pancreatic cancer.

3. Occidental Petroleum

Warren Buffett bought eight stocks in the third quarter of 2022. Occidental Petroleum (OXY 1.01%) was one of them. Should you buy the oil stock before year-end just because the legendary investor has scooped up shares? Nope. However, there is a reason to buy Occidental soon that involves Buffett.

As of the latest available data, Berkshire Hathaway owns 21.4% of Occidental. But the giant conglomerate received regulatory approval in August to buy up to 50% of the oil and gas producer. This means that Buffett is almost certainly going to add heavily to Berkshire's position.

We don't know how quickly Berkshire will increase its stake dramatically in Occidental. If and when that happens, Occidental's stock will likely shoot up even more than it has so far. If you want to profit from that scenario, buying Occidental sooner rather than later makes sense.