Two Canadian companies have teamed up to bid at least $18 million for

Hudson’s Bay Co. ‘s Royal Charter, a historical document that gave it exclusive trading rights over a portion of Canada in 1670.

Wittington Investments Ltd., a private entity owned by the Weston family, and DKRT Family Corp., owned by

David Thomson , Canada’s richest person, will bid at least $18 million when the auction for the charter takes place early next month, according to court documents released Nov. 14.

Previously, both Wittington and DKRT had put in separate bids to buy the charter. HBC in June said it had reached a $12.5-million deal to sell the charter to Wittington. But the company in August said it had another offer of at least $15 million from DKRT.

As a result, HBC decided to host a separate auction for the charter and sought approval for it from an Ontario court on Sept. 29. However, HBC’s lawyers told the court that they wanted an adjournment since the company had received another bid for the charter, which turned out to be the joint proposal from Wittington and DKRT.

The joint bid will allow HBC to get a better price for the charter, which could result in increased recoveries for its creditors. The joint bidders would donate the charter to a consortium made up of four Canadian public institutions, including the Archives of Manitoba, Manitoba Museum, Canadian Museum of History and Royal Ontario Museum.

It also committed to donate $5 million to “fund stewardship, consultation, education and public access related to the charter,” the court document said. This is higher than the $2-million and $1-million donations that DKRT and Wittington had respectively committed to in their separate bids.

Any other party interested in taking part in the auction will have to submit their proposals by Nov. 28.

The sale of the charter is just one of the steps HBC has taken to pay back its creditors, from whom the company sought protection in court earlier this year. The company is also trying to sell other artifacts it owns, and it has already sold its intellectual property rights and leases.

The process of selling the Royal Charter has garnered plenty of interest due to its historical importance.

HBC’s lawyers will try to approve the process to sell the charter at an Ontario court on Nov. 21.