North American Industry Classification System (NAICS). NAICS uses a hierarchical structure with sectors represented by 2-digit codes, such as Manufacturing (31-33) or Retail Trade (44-45).

In antitrust law, a "market" is defined as an area of effective competition that includes both product (or service) and geographic dimensions. The US Department of Justice and Federal Trade Commission use market definitions to evaluate competition under laws like the Clayton Act.

Tools like the hypothetical monopolist test are used to determine whether a market is too narrow by assessing if a monopolist could profitably raise prices.

> Also, if you invent something so novel it makes a new market, that would imply you are immediately taxed at 100%.

Fine, pick some fractional coefficient.

I'd be more inclined to scale it based on total revenue. There's a big difference between having 100% of a new market you just recently created that only makes $1M/year and having 90% of a decade-old market that makes $10B/year.

(That said, there are a hundred other things that'd need fixing for such a hypothetical to be viable, let alone desirable. This was just the thing that stood out the most to me, particularly on a site centered around startups.)

> Also, if you invent something so novel it makes a new market

That's innovation, which is not the issue here. Creating new markets is usually win-win (initially), even with big tech leading the way.

The more damaging issue is in taking over existing markets in ways that do not benefit that market. e.g Big tech Moving into film and TV, it's not simply a buyout with massive capital, it's about burning money in one ancillary market to benefit their primary market, but usually at a detriment to the ancillary one. They are unfairly leveraging their primary market position, tying products together, even if they don't ever make any profit in the movies, they create more and more lock-in with their platforms, making it harder and harder to not use them. The overall affect, more profit, without a chance of competition.

Does this mean google should not do AI research, or enter into any AI related sector by leveraging its ad money? Or Meta?

Should Microsoft have stayed with just BASIC compiler? Should it be illegal for it to enter operating systems market? What about productivity suite?

Bundling is explicitly recognized as antitrust concern. Using a monopoly in one area to undercut a competitor is what Microsoft and Google were both found guilty of by the DoJ, so it's funny you should mention them. It's not about being prohibited from developing new products, but in how you price them, and giving away things for free because you can afford to due to your monopoly in one area, and your competitors can't is the crime, or forcing people to buy both of your products together at the same time, is the problem, as enforced by the DoJ. Google should be free to develop Chrome, but funding all of its development from advertising profit and then giving it away for free because you can because you have a monopoly in search advertising is the problem, because Mozilla doesn't have search advertising monopoly money or desktop operating system monopoly to be able to give their browser away for free and fund further development from those sales. This is why, as part of the Google breakup is for them to sell off Chrome.

This also means google should not give away for free any of their gmail service, youtube?, chrome, maps or any such thing. All of these are funded by the ad money

> That's innovation, which is not the issue here. Creating new markets is usually win-win

You're preaching to the choir here. The post I was replying to described a policy that would have made that an issue, without some way of addressing that case.

I said there would be loopholes right :-)