Is Warren Buffett's investment theory still relevant today?

Actually, Warren Buffett's investment theory hasn't become outdated; on the contrary, many people are still learning from it.

His core principles are just a few: buying stocks means buying companies, so choose businesses that are simple to understand, generate stable profits, and have reliable management; buy when the price is right, don't chase highs; and once you buy, hold onto it, don't constantly tinker.

The market is changing rapidly now, with AI one moment and new energy the next. But if you look at those who genuinely make money over the long term, they are still buying large companies in traditional sectors like consumer goods, finance, and energy—many of which are the same ones Buffett bought.

Moreover, he has always emphasized "never invest in a business you cannot understand." Nowadays, various new concepts are flying around, like the metaverse and blockchain, which sound sophisticated. But if ordinary people truly can't figure out how to make money from them, then listening to him and not acting rashly is the right thing to do.

Of course, times have changed, and blindly copying him won't work. For example, he used to largely avoid tech stocks, but now companies like Apple have become giants combining "consumer + technology," and he has bought quite a bit of it. This shows that he himself is slowly adjusting.

So, it's not that his theory is obsolete, but rather that one needs to understand the logic behind it—buy companies, look at value, don't be greedy, and control your impulses. These principles are timeless. The key is whether you can remain calm and not be swayed by short-term fluctuations.