As 2025 hurtles towards its close, the turn of the calendar is a great time to take stock of both our stock market portfolios and our investing habits and assess if they are fit for 2026.
It has been a profitable, if a little volatile, year for investors in 2025. The S&P/ASX 200 Index (ASX: XJO) is up 6.04% since 1 January as it currently stands, while the American S&P 500 Index (SP: .INX) has put on a more impressive 16.46%.
But as to what 2026 might bring? No one knows.
With that in mind, here are three golden rules of investing that I think most investors will benefit from following into the new year and beyond.
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3 golden rules of stock market investing for 2026
Have a plan and stick to it
Most investors will tell you they have a plan, but when markets start doing things that we don't like, that plan often gets thrown out the window. The old saying about fixing the roof when the sun is shining applies well here. As we venture out into 2026, take some time to take a look at each of your portfolio's positions, why they are there, and what you think might happen to them if markets get a serious case of the wobbles. It's best to trim or sell out of companies that you might not have faith in when everything is rosy. Not when investors are panic-selling.
So why not take the opportunity to take a look at your entire portfolio over the Christmas break, and decide what you'd like to see from it next year? I'm already preparing a watchlist for 2026 so that any dividends or surplus cash I enjoy next year will quickly find a new home.
Ignore the fads
One of the most consistent trends in investing is the emergence of fads. One year it might be lithium or battery stocks, the next, uranium miners, cryptocurrency shares, or AI stocks.
These fads tend to see huge amounts of money rush into any company that might possibly stand to benefit from a future trend. It is usually an illogical and exuberant phenomenon to watch, and one that tends to fizzle out at some point. This is usually built on an initial trend that offers a genuine opportunity. But it eventually gets ahead of itself as investors become so excited at the prospect of a quick buck that fundamentals are forgotten.
These fads can be dangerous for investors, and in my experience, are best avoided. Keep an eye out for whatever craze hooks investors in 2026. It could be AI, or some other hot corner of the market where investors start to see unlimited upsides that don't eventuate.
Focus on the stock market basics
I heard a fair bit of 'there's a stock market crash just around the corner' in 2025. No doubt those calls will grow louder in 2026, particularly if the S&P 500 starts to look like it is headed for another 16% year. Eventually, there will be another market crash. History teaches us that it is inevitable. However, no one knows whether the next one will be in 2026, 2028, or 2035.
It is foolish, at least in my opinion, to base investment decisions on what you might think will happen to the entire market down the road. I don't even look at what's going on in the economy. All I focus on with my investments is whether 'the company is growing at a healthy pace, and how likely is it to continue to grow'. The best companies can survive and thrive in all economic climates. So I think sticking to investing fundamentals and finding those companies is the best way to devote your investing time in 2026.
