Warren Buffett's massive stock sale has 3 important lessons for all investors

The famous investor Warren Buffett started the year with a big share in it an apple (NASDAQ: AAPL).

In fact, it was the largest share held by his company, Berkshire Hathawayto any listed company. In recent weeks it has emerged that Buffett has sold nearly $75bn worth of Apple shares since the start of the year.

Does that mean he has changed companies? That's not the case. After all, he continues to play a major role in Apple even after the sale, as far as we know.

In addition, Buffett has not publicly discussed the reason for the sale. However, I think there are three very good lessons to be taken from it for all investors.

1. Stocks are investments, not life partners

Does Warren Buffett like Apple?

It has the hallmarks of a classic Buffett purchase: a large market of potential buyers, proprietary technology, a well-established brand, and attractive profit margins. The investment has been very profitable for Berkshire.

But that's exactly what it is: an investment.

Buffett is a rational investor focused on financial success, not an emotional lover of stocks.

It is easy to become emotionally attached and possessive, if only for pride. Buffett sometimes sounds like he likes certain stocks – but really, he's a financial investor, pure and simple.

2. The issue of diversity

Buffett's sale of more Apple shares also helps mitigate one of the challenges I think Berkshire was facing.

As Apple stock had soared (it has more than tripled in the past five years, which further underscores that Buffett is a shrewd investor), he represented a large portion of Berkshire's portfolio of publicly traded stocks.

An investor of any size, from beginners to Buffett, needs to manage risk.

Keeping the portfolio properly diversified is an important part of that. One can become a victim of one's own success in this sense. As Apple rose, it ended up taking a much larger portion of Berkshire's portfolio.

However, diversity is always a good idea. The sale of some Apple shares is a good example of that.

3. Trying to time the market accurately is a mug's game

Apple's stock price has risen to its highest level since the first half of the year, when Warren Buffett sold.

So, did you sell early?

In fairness, one of the contributors to that price may have been Buffett selling more shares in the first quarter.

But the bigger point in my opinion is that Buffett is looking at what he has versus what he thinks he deserves. That's different from trying to time the highest value and exit early.

Apple may go down from here, due to high valuations and declining sales. Again, those factors have held true all year — and Apple has already gained 20% anyway. It may go higher at the moment.

Rather than trying to precisely time the market – the cup game – Buffett took a lot of money off the table and put a very clean profit into the process.