Concentration to potentially build wealth or lose it all
Diversification to more likely protect wealth
Fixed it for you 
You are of course correct in most of what you say 
Just need that caveat of no matter how much research you do it can still go tits up.
Of course youāre right and itās all about your appetite for risk management. An important point is not to buy in all at once - buy more as your conviction gets stronger, if there are negative developments donāt be afraid to sell and take a loss
But it should be noted that stocks usually donāt go to zero, you can estimate the value of a public company, how the value will drop if things go badly. If youāre already up say, 50%, 100% with a certain stock (and not for transient reasons like a reddit pump, but actual reasons you understand such as generation of revenue), then your risk of ālosing it allā is extremely low. Despite not being diversified
Ofc the risk is still there - what if thereās some fraud scandal, or some other freak event. Itās good to hedge against that. I just think itās underrated - high conviction long term investing. The main caveat is to treat it like another job in itself. And if you donāt find that enjoyable or donāt have the time, then put money into SPY or a diversified portfolio instead (usually SPY wins)
āStocks usually donāt go to zeroā is a big survivorship bias. How many of the biggest stocks from 50 years ago are still around? How many got bought out after declining in price significantly?
Especially with blue chips, itās not smart to put everything in one basket. The expected return of most blue chips is roughly the same. But by buying many of them, you can lower your risk while keeping the same expected return.
Smaller companies on the other hand are very risky, upside and downside. If you want to put all in one of these companies, you can also just go to the casino and put everything on red. As an outsider you will never have more information that the market on any company, so doing research is just a plain waste of time for almost every investor.
Itās a mathematical equation of risk vs. reward. You should attribute a risk factor to your estimated gains and optimise for maximum return.
Personally, I invest on the assumption that my income will increase over time so my investments become proportionally less important. For that reason I treat all of my investing as a learning process. I invest in companies that I am interested in and to date have never sold. I own 30-40 stocks, I started off with an investment size of about Ā£200 for each investment. Now itās Ā£500 for every new investment.
I am happy to invest in many different stocks as it accelerates the learning process. I have a few different brokers, but these are my Freetrade returns to date:
Edit: Actually, that graph doesnāt go back far enough. Iām up ~140%:
I strongly disagree with the sentiment in this post especially the last paragraph where you say research is a waste of time for investors. There is so much information available. So much opportunity out there on the market. It should be obvious to everyone who has been in the market for a while that the market is not perfect at assigning value, far from it, share price is often a poor reflection of value which is why value investing is a thing. Many stocks are over-valued and many are under-valued
A single investor is not able to value a large portfolio of companies and work this out for all of them. But it is more than possible if you focus on a few
Iām not sure why you think people donāt have a chance against the collective market if you have your own strategy and youāre well-researched. Itās a negative outlook and not true. Itās not like day trading which is a losing proposition because youāre competing with the algorithms. Youāre not competing with hedge funds - they have completely different strategies to retail investors. The main competition is with your own psychology because you have to recognise that share price often doesnāt reflect value
You mentioned blue chips, the strategy I discussed is more for small and mid caps. A few exceptions aside thereās not much growth in blue chips
The kind of investing Iām talking about is as far from the casino as you could get
We can always come back to risk but you know: thereās a risk Iāll get run over by a bus on my way to work, thereās a risk Iāll get cancer tomorrow, thereās a risk Iāll get shanked by some angry coked up person after a night outā¦ Try and avoid all risks and youāll never get anywhere or do anything
Cool and Iām happy for you. But this just doubles down on biases such as survirvorship bias. Youāre one out of a couple of million British investors. All the people that lost lots of money instead will never post about it, so it will just be āsurvivorsā high-fiving each other and giving new starters a distorted view on reality. 
How do you discriminate between survivorship bias and skill-based success? Not everything is luck, otherwise donāt buy any individual stocks ever and only have the broadest investment possible.
That may be right for some or most people, but that doesnāt mean that intentional success is not possible.
In summary: be unemotional, read Peter Lynch and invest long-term.
Those concepts arenāt related. The bias occurs because we only ever see the successful people. If they were skilled or lucky is irrelevant. Have you ever seen someone post about being down 90% on their portfolio? Of course not. That gives us a massively distorted view as if these people didnāt exist. They do though.
I personally donāt think thereās much skill involved, but almost everything is down to āluckā. As you said, the broadest investment is indeed the best way to invest in the long run (or at the least broad enough to diversify against unsystematic risk). But that has nothing to do with the above question.
Suggested readings: A random walk down wall street, The Black Swan. Or any quantitative finance book.
I donāt know how you can say itās all down to luck when there are demonstrably so many ways to differentiate a good company from a bad company, and so many things itās possible to learn about. There are plenty of factors out of your control - but thatās true in all aspects of life, not just investing
https://www.reddit.com/r/CanaryWharfBets/
Come join the party, dude! 
Thatās not what I meant at all, btw. I said that may be best for some or even most people, depending on their personality type or how much effort they want to put in to investing. Someone like Peter Lynch who is investing in thousands of different stocks for over a decade and massively beating the market is extremely difficult to attribute to luck. You would need to have a ridiculously small probability for that number of investments to give that much success and be down to luck.
Haha, nice one!
Actually, individual continued success is extremely easily explained by luck. Assuming investment return follow a normal distribution (which they do not, but thatās irrelevant here), there are always some people on both tail ends. So with billions of people investing in the world, thereās bound to be dozens outperforming constantly by āluckā.
Not true. Letās estimate Peter Lynch invested in 10,000 stocks over his career, which seems like a fair estimate seeing as he managed his fund for 13 years and had over 1,000 stocks at one point.
If we estimate that the probability of success of investment in a stock is 50%, equivalent to flipping a coin and half the results being positive and half being negative. We then estimate that he had a success rate of 55%, that would give a probability of that level of success (or greater) of about 1 in 10^23.
Even with billions of people investing, letās say 5 billion, that would give a probability of one of those individuals having that level of success as 1 in 2 x 10^13 (one in 20 trillion) chance of that happening due to luck.
You can play around with the numbers, but they dispute that that level of success is attributable to luck.
But your math makes no sense. Itās like someone with GCSE math trying to do higher maths.
No offence mate, but I think our backgrounds are just so different that we canāt be made to understand each other in a simple message thread.
You need money to make money, simple dimple pop it, simple dimple pop it.
Itās binomial distribution, the chance of 55% or more coin flips being heads after 10,000 flips. The point is that success is easily attributable to luck with a small number of trades, but once you start getting to the thousands it is statistically less likely to be attributable to luck. Not sure what your background is, I did masterās in engineering. Pretty sure the calculations make sense.
Aside from that, Iāve read some of his books and it makes sense to me and has given me success in the last few years but I could be one of the dozens out of the billions.
A lot of successful traders or investors are successful mostly because of good risk management and money management.
They will also ditch their losers very quickly and concentrate on their winners. Itās the opposite of what many people on forums like this do, Most retail investors double down on losers in the hope of getting back to break even and end up over exposed to a losing position.
Itās a lot easier to do this if you are well diversified. Itās easier to dump a loser if you arenāt all in, and emotionally invested in it
Yeah, but you donāt model stock returns with a binomial distribution, same as you donāt model the weather with a binomial distribution. Both are complex systems. Letās stop this before I start asking which uni gave you that engineering degree.
If youāve got a better model for showing that investing is purely luck then Iād be interested to see it.
Was there not a study where monkeys outperformed fund managers?
Wouldnāt surprise me - but retail investing is a world apart from fund managers, who have certain limitations, certain specific goals, and most damaging of all, have to provide their clients with quarterly / whatever updates in how the portfolio is doing. I donāt have to worry about clients calling me because the line is going down
For people who donāt want to manage their own money, it doesnāt get much better than SPY
