The late, great David Webb, who was a champion of market transparency and the small retail investor, used to tweet out High Concentration of Shareholding Notices from Hong Kong’s Securities and Futures Commission (SFC).

Essentially, the SFC will point out companies listed on the Hong Kong stock exchange in which a small group of— say, 30 or fewer— investors own a large combined stake (usually over 90%) of the company, AND whose share prices have risen a substantial amount over a short amount of time. With such a small group of investors with nearly all the shares, there may be relatively few shares available for trade, making its stock price unusually easy to move. So the Notice serves as a warning to retail investors that sharp fluctuations in prices are more likely. It does not necessarily mean anyone involved in the company has done anything sketchy or even illegal; it’s just a warning.

Since David’s passing, I have skeeted High Concentration Notices on Bluesky, and now, as a public service, here is a spreadsheet with the complete list of High Shareholding notices from the SFC since December 2025. You’ll see the company under notice, its share price on a reference date and on the day before the Notice was issued, plus the percentage change in share prices during that period. Because this is Google Sheets, you’ll also find the current share price (with a 20 minute delay), thanks to the =googlefinance() command.

If time permits, I will add older notices before December 2025. I will continue to post new high concentration of shareholding notices on Bluesky when they appear on my news feed, and the table will be updated at the same time.

More of David’s past work will be featured in The Numberwang; stay tuned.