There's no definitive way to see a company's worth.

What you're referring to is book value.  That is what the company would be worth assuming you wanted to buy the company and just liquidate all of its assets.  But it doesn't take into account future earnings and such.  But it doesn't take into account future potential, and a number of other things.  It's somewhat useful, but nobody would really use it to determine the actual value of a company.  Like, if someone wanted to buy Sony, there's basically a 0% chance they'd be paying exactly the book value.

Right, it doesn't take into account the subjective and speculative side of doing bussiness. 

You just need to look at the front page to see why. The PS4 has a mature user base, while the Switch is just starting to grow.

I couldn't find profit broken out for just the network, but I did find it for the division. Revenue for the six months ending September 30 was 781,266 million yen. Profit was 72,483 million yen. So about a 9.3% profit margin.

Nintendo over the same time period was 374,041 in revenue and 39,961 in profit. So about a 10.7% profit margin. Not a big difference in margin there.

But the big money for the video game industry always happens during the holiday season, so the six months ending September 30 might be the least interesting time there is.

I think an educated guess based on the launch numbers of the WiiU and 3DS could help.

But yeah it will be easier to compare after we get to the end of the first year for the Switch.

Sony has a lot of bad apples among its operating units, with most of them losing money for years or fluctuating over the years. Even then, Sony has a lot of competition in those industries and isn't a top competitor in them. Even when you look at the consistently profitable segments, like music, they don't make enough. The only segment that is doing as well as games is insurance, which is a separate subsidiary. At the same time, there is more risk for Sony. They have weaker liquidity and more debt. 

Nintendo, on the other hand, has a lot of potentials. They have a large portfolio of IPs that can be leveraged into other products and mobile games. They have the legacy systems and of course the hardware/software business. The company has little debt, pays a constant dividend and is flushed with cash, giving them plenty of opportunities for M&A activities. Nintendo has a better outlook for growth with levering their IPs, the Switch selling well, and expanding into other markets. 

As for the income, keep in mind Sony has a larger install base. This means more revenue from PSPlus and licensing fees from software developers. This will change as the Switch install base grows and the online service kicks in.

What?! That's not how companies get valuated. Maybe internally, but to critics (like Forbes who make those lists) and investors, it's easy to see that it's not the case.

To an accountant that's exactly how they would value companies, through "total equity" ... 

With investors and stocks, it's totally based on speculation ... 

I quite like using total equity as a measure of worth since it's more grounded but even that's still subject to speculation ... 

There is only value in something if people believe it to have value such as money even though it's just printed paper ... 

What he described is book value per share. Its a good measure since it, in essence, the amount the company is worth if you liquidated all its assets. If you are looking at a stock, it may not be bad to know since you can tell if the market is vastly overvaluing or undervaluing. 

There are two reasons that the book value and the market value are different. First, per GAAP, assets are measured at historical cost, with some exceptions. This means if you have, say, a building that you've owned for 30 years and has appreciated in value, it would still be recorded at price you bought it. The other is that there are some nontangibles the company may have that can't be booked. For instance, a company could have an amazing brand that makes it more valuable than what the financial statements are showing. In the stock market, future potential plays a lot into the price as well. 

Their semiconductor business seems pretty solid too. "Sony's semiconductor business saw profit of 49.4 billion yen in the quarter, up from a 4.2 billion yen loss in same period a year before. The loss was due to an earthquake which hit production.