Glencore Plc said it’s willing to raise its bid for Teck Resources Ltd. in the latest attempt to sway shareholders and pressure Teck’s board, with just one week to go before a pivotal vote on the Canadian miner’s future.

The companies have spent the past few weeks in a bruising fight to win over Teck investors, after its board and controlling shareholder publicly rejected Glencore’s proposal. The Swiss commodities giant offered to buy Teck for US$23 billion and then create two new companies combining their respective metals and coal businesses.

Teck is pressing ahead instead with an earlier plan to spin off its own coal mines — with an investor vote scheduled for April 26 — while raising the possibility of a sale afterward.

With the prospect of a higher bid, Glencore is hoping to convince enough shareholders to either reject the split or pressure Teck’s board to delay the vote and enter talks. Glencore is prepared to raise its offer, the company said on Wednesday, but believes any improvement should come after discussions with the board.

If Teck still refuses to engage — and if its split does not proceed — then Glencore said it’s willing to put its offer directly to shareholders.

The threat to go hostile ratchets up the tension in a drama-filled public battle that has already seen both CEOs rushing to Toronto last week to pitch their plans. The fight has gotten ugly at times — Teck pointing to Glencore’s record of bribery and price fixing — and has drawn in some of the biggest names in Canadian mining. It’s a potentially company-defining moment for both Glencore and Teck, as they wrestle with the future of their giant coal businesses while seeking to expand in metals like copper that will benefit from the energy transition.

Any attempt by Glencore to circumvent Teck’s board would face significant hurdles without support from its founding family, the Keevils, who have a blocking vote because they dominate the company’s “supervoting” Class A shares. Norman Keevil, the 85-year-old patriarch, has come out strongly against the Glencore proposal, while offering investors the prospect of a future sale after Teck’s split is complete.

Keevil was quoted early in the saga saying that he would not sell to Glencore at any price, and that “Canada is not for sale.” But he seemed to have softened his position by last week, saying in an interview with the Globe and Mail that he can’t go against what the majority of other shareholders want, although he still opposes Glencore’s offer.

SHAREHOLDER PRESSURE

Teck’s plan to split its company requires two-thirds approval from both sets of shareholders — the “A” shares dominated by the Keevil family, as well as the regular Class B shares, meaning Keevil can’t use his sway to force the separation through.

Teck’s Class B shares dropped 0.2 per cent to C$64.32 at 9:44 a.m. in Toronto trading. Glencore was down 0.8 per cent in London.

Glencore’s pitch gained momentum in the past week when two influential shareholder advisory firms recommended a vote against Teck’s split on April 26. Bloomberg also reported that Teck’s largest investor, China Investment Corp., favored Glencore’s proposal for the coal business — though had yet to decide how it will vote.

Still, some investors may be disappointed that Glencore has not yet announced an increase to its initial proposal. The company originally offered to buy Teck for US$23 billion in shares, at a 20 per cent premium to its value at the time. It later adjusted the terms by offering a cash component to buy Teck shareholders out of the combined coal company that it plans to create.

And the Canadian company has also gone on the offensive in the last few days. Chief Executive Officer Jonathan Price told investors Tuesday that the company’s shares could eventually trade at levels more than 70 per cent higher than where the stock is now, and warned that Glencore’s offer would take at least two years to execute.

Teck’s shares surged to a record on Monday, exceeding the per-share value of its offer for the first time after Keevil’s statement, and reports that other major mining companies had showed interest in a deal for its metals operations after the split.

Bloomberg has reported that the world’s biggest mining companies have a renewed appetite for large deals, and Teck’s copper and zinc mines have long been admired by its rivals.