According to documents and four people with knowledge of the decision, Maroil Trading, owned by shipping magnate Wilmer Ruperti, has taken over sales of nearly all of Venezuela’s petroleum coke exports, a move that could minimize sanctions risks for clients, Reuters reported.

Since entering a business agreement with state-run oil corporation PDVSA six years ago, the Geneva-based company has increased exports and clients. Due to U.S. sanctions on Venezuela’s oil industry, Maroil has assisted in sustaining shipments of petcoke, a byproduct of crude upgrading and refining that is commonly used by cement manufacturers to fuel kilns.

Shipping paperwork and two of the individuals claim that, at least since August, all petcoke cargoes leaving PDVSA’s Jose terminal on Venezuela’s eastern coast have been through Maroil, leaving the state oil company to export a minimal volume from its Cardon refinery.

“Maroil has taken over the cargo handling out of Jose completely,” said a person acting as agent for customers. “For clients, this is way more efficient than dealing with PDVSA.”

According to papers Reuters has access to that span four months’ worth of shipments, trading petcoke may be extremely profitable.

Petcoke delivered from PDVSA’s Petrocedeno facility and transported on tanker Arki was charged to Maroil in April at a rate of $45 per tonne. Invoices and customs records revealed that a month later, a cement company paid a reseller $220 per tonne for the cargo upon arrival in India’s Jaigad port.