Apple's missing 2001 10-K
Apple did not file a 10-K annual report in 2001. Or did they? Let's use edgartools and AI search to get to the bottom of this
There is an Apple 10-K filing on Edgar every year since 1994 - except for a gap in 2001.

This is problematic if you are doing filing analysis and have to account for missing data in one of the largest and most important companies in the world. So why the gap?
This question was raised as an edgartools Github issue. I spent some time looking into it - ok I spent around 10 minutes.
Grokking the 10-K
I started with Grok which was very confident that Apple filed a 10-K in 2001

So I called Grok's bluff and asked it to find it.

Grok got frustrated really easily and we were still 60 seconds into the research. If I had a junior researcher on staff who got frustrated that easily I'd have a serious talk. And if we have to live with that level of emotionality after we achieve AGI in 2027 we humans will be in a lot of trouble.
Then Grok settled on the absence being due to a stock option back-dating scandal, though intelligently it used wording that probably saved it from an Apple lawsuit.

Perplexity to the rescue
Next up I asked Perplexity to find Apple's 10K filing from 2001. I don't have paid Perplexity but I was hopeful for a good experience. I was not disappointed.

It found information about the 2001 filing pretty quickly and showed key details from it in the results. It also linked to the filing and Apple press releases.
However when I opened the filing it was a form 10-K405 which I was unfamiliar with.

Much ado about checkbox 405?
So Apple did file an annual report in 2001. However the SEC had a rule that if you selected checkbox 405, then the filing would be a 10-K405 instead of a 10-K.
So what was in checkbox 405? Actually nothing. Prior to 2003, companies were required to disclose whether any officers or directors failed to timely file Form 4 (used to report insider stock transactions). If the box was checked, the filing became a 10-K405.
This was a bad rule and a bad design for the Edgar system and for good reason it was discontinued in 2001. It's also a quirk to be careful about when researching and analyzing filings.
Different research tools
I try to use different tools when researching and coding. For this specific query Perplexity was better than Grok. I also just tried Google for comparison and it was actually very good - both the traditional search and AI Overview found the 2001 filing.

Conclusion
edgartools tries to make it easy to find anything on SEC Edgar. Occasionally we find these quirks in the underlying data that can cause issues in your analysis, but it can also be fun to hunt down for actual explanations. It's also a good practice to use the different tools to augment your research.
If you use Python for financial analysis give edgartools a try. You can pip install edgartools
and give a Github Repo a star.