Those who have been following the saga of "Belgium's" US Treasury holdings learned last month that the "mysterious buyer" behind Belgium's Euroclear was, as some speculated, China all along. Nowhere was this more evident than when showing an overlay of China and Belgium's combined TSY holdings versus China's forex reserves.

This is what we concluded last month:

"Belgium" is, or rather, was a front for China: either SAFE, CIC, or the PBOC itself.

That Belgium's holdings, after soaring as high as $381 billion a year ago, have since tumbled back to only $2532 billon as China has dumped the bulk of its Euroclear custody holdings, and that once this number is back to its historical level of around $170-$180 billion, "Belgium" will again be just Belgium.

China's foreign reserves tumbled and this was offset by a the biggest quarterly drop in Chinese pro-forma treasury holdings, which dropped by a record $72 billion in the month of March, and a record $113 billion for the quarter.

It wasn't precisely clear just why China, which had historically used UK-based offshore banks to transact in US paper in addition to the mainland, would pick Belgium or why it chose to hide its transactions in such a crude way, however the recent accelerated capital outflow from China manifesting in a plunge in Chinese forex reserves, coupled with a record monthly liquidation in total Chinese holdings, exposed just where China was trading.

And while we have yet to get an update from Beijing of its April forex reserves, we know that China's Treasury liquidation has continued. Enter: Belgium, only this time it is not a "mystery" buyer behind the small central European country, but a seller.

As the chart below shows, after a record $92.5 billion drop in March, "Belgium" sold another $24 billion in April, bringing the total liquidation to a whopping $116.4 billion for the months of March and April.

This means that after adding mainland China's token increase of $2 billion in April after a $37 billion increase the month before, net of Belgium's liquidation China has sold a record $77 billion in Treasurys in the most recent two months.

And while we eagerly await the monthly update of Chinese official forex reserves, we can estimate that the drop will be another $50-60 billion in the month of April.

The good news, for those tracking the story of China's unprecedented capital outflows, is that after "Belgium's" record March dump, in April Chinese Treasury sales slowed to the slowest pace in the past three months.

In other words, China may finally be getting its capital outflow problem under control, which, incidentally is bad news for the Chinese stock market because if true, it means the PBOC can now step back from micro-managing the stock market bubble and its "beneficial" current account inflows to offset the declining capital account.

But what is perhaps most curious is that even with China liquidating such a massive amount of US paper into a very illiquid market, the yield on the 10Y did not blow out far more in the months of March or April. And the last question: who did China sell all this paper to?