As in so many housing bubbles, soaring apartment prices feed epic high-rise construction booms with the promise of big profits backed by easy money. Years can pass between initial plan and completion, and now the fruits of Hong Kong's epic construction boom are hitting the market just when prices are crashing and sales collapsing.

In the first quarter, the number of housing units under construction set a new frenetic record: 13,300, the South China Morning Postreported, citing the Transport and Housing Bureau. By comparison, in all of last year, 14,200 homes were under construction. In 2015, 11,300 new homes were completed. This year, the number will jump 61% to 18,200! Over the next three to four years, 92,000 new homes will hit the market.

And this is happening just as home sales are plunging. According to the Rating and Valuation Department's April Property Review, sales for January and February – the most recent months included – plunged 69% from a year ago to 3,852 homes. February's 1,807 home sales was a 25-year low.