He apprenticed as a merchant and working in Portugal, the Netherlands and England in 1765-68 where he achieved a great knowledge of international trade, especially with respect to East Indian colonial goods.

He generated average sales of DKK 2 million during his best years but twice had to apply for court receivership due to the baldness with which he managed his affairs.

He had close ties to finance minister Ernst von Schimmelmann who provided him with advance payments in return for his advice to the government.

From 1799, Denmark experienced a period of economic crisis which hit Peschier's trading house hard but he was helped adverse times by credits from Bankkontoret.

In 1804, the ties between the state and Peschier's trading house became even closer and both his nephew Agier Wexelsen from Bankkontoret were made partners in the company.