Via Avbrief.com, Sonex is shutting down immediately.

Mark Schaible, owner of Sonex, said "This decision is necessitated by a severe drop-off in sales and our bank’s unwillingness to carry-forward our debts given some unprofitable years. We’ve had to make this decision very suddenly as a perfect storm of bank pressure, lack of sales, increasing costs, competition from our own aircraft in the used market, and cashflow realities are not allowing us to continue our work."

https://avbrief.com/sonex-shuts-down