I'm not an economist, nor am I an expert on China, but according to this recent FT article, more than half of the country's largest developers (based on 2020 sales) are now in default:

On top of this, there's a lot currently in the pipeline:

The National Bureau of Statistics of China is saying that, as of last August, there was about 8 billion square meters of real estate under construction in the country. That's very roughly about 80 billion square feet of space, which I'm assuming covers all asset classes.

This is such a big number that I really have no idea if it's excessive or not for a country that is rapidly urbanizing and has some 1.4 billion people. So let's compare it to the US.

Back in 2020, Brian Potter came up with estimates for the entire US building stock. Interestingly enough, he determined that about 90% of buildings in the US are single-family homes. This is what the US builds and continues to build, by a long shot.

However, single-family homes do tend to be smaller than, say, office buildings. So if you instead look at square footage (and not the number of buildings), this percentage drops to about 60% of all buildings in the US.

On a square footage basis, single-family homes are estimated to represent about 200 billion square feet. And in total, Brian estimated the entire US building stock to be around 340 billion square feet (again as of 2020).

This means that, right now, China could have nearly 25% of the entire US building stock under construction. I think that seems like a lot.

Images: FT