Companies are allowed to sell production rights, so long as the transaction is reported to the government.

Alberta oil producers have found a way around production limits imposed on them by the provincial government: buy the right to pump barrels from other companies that don’t need them.

The volumes aren’t huge — Husky Energy is buying rights to produce an additional amount of less than 1,000 barrels a day, Rob Symonds, chief operating officer, said recently in an investor call. It’s not a transparent market, mostly operating “by people phoning people,” Robert Peabody, chief executive officer, said in the call.

“It is a company-to-company market,” Symonds said. “It’s personal contracts.”

Alberta’s government imposed limits on producers starting to alleviate an oil glut caused by a lack of pipelines that sent heavy Canadian crude plunging in October to $50 a barrel below benchmark West Texas Intermediate futures. The province said in January it would ease the curtailments as prices strengthened to an extent that shipping crude by rail became less economic.

Pengrowth Energy, an oil sands producer, has been “actively engaged in this secondary market,” Tom McMillan, spokesman, told Bloomberg.

A buyer of rights to produce will generally pay less than the value of the barrel to ensure a return, McMillan said. “The price you pay per barrel would need to strike a balance so that each barrel you produced creates incremental earnings.”

Rules on the curtailment allow companies to sell production rights so long as the transaction is reported to the government. Alberta’s government allowed such trades to ensure flexibility and also ensure that the province’s output doesn’t fall below the limits imposed.

The market is set to grow as spring approaches and companies shut equipment for maintenance.

Alberta’s curtailment plan wasn’t an ideal solution but it was applied “fairly and equitably,” Mike McKinnon, a government spokesman, told Bloomberg by email. “We know that our plan is working to lower the oil price differential and save jobs across the energy sector.”

A Husky spokesman said it can’t disclose which company it bought barrels from for confidentiality reasons. The curtailments apply to 28 producers that pump 10,000 barrels a day or more.