Mason asked the Supreme Court of British Columbia on Tuesday to order Telus to provide unredacted copies of the proxies submitted ahead of a vote on whether to eliminate the company's dual-class share structure —a move Mason vehemently opposed.
Telus withdrew the proposal just before the matter came to a vote at the company's annual meeting in May but the sparring between the two sides has continued.
The telecom giant earlier complied with Mason's request for copies of the proxies after Mason sought an order from the B.C. Registrar of Companies.
But Mason complained that sections relating to the proposed share consolidation were blocked out and the New York-based investor could not tell how shareholders voted. It also said that Telus provided results from only common shares, not non-voting shares.
Telus has said it continues to support having a single class of shares, a move that Mason argues would reduce the value of its voting shares and increase the value of shares that currently don't have voting rights.
The two classes of shares originally enabled Telus to comply with Canadian law limiting foreign control of telecom companies.
The hedge fund, which owns almost 20 per cent of Telus, says in the petition that knowing the level of support for the proposal could affect Mason's decision about whether it should increase or decrease its stake in the telecom company.
Mason's petition says, among other things, that it has the right to inspect Telus' ballots and proxies.
"The level of support for the proposed arrangement from holders of voting shares directly relevant in determining the likelihood of success of a future proposal by Telus to effect a one-for-one share conversion," it said in the court filing.
"(That) could materially affect Mason's decision as to whether to increase or decrease its substantial position in Telus' securities."
Telus has repeatedly accused New York-based Mason Capital Management of manipulating the market for short-term financial gain with a practice called "empty voting,'' a strategy of essentially borrowing shares to increase voting power while limiting investment in a company.
It has said Mason owns 33 million voting shares, or 19 per cent, and shorted almost the same amount in non-voting shares, essentially betting the price of those shares will fall if the share consolidation plan is defeated.
Spokesman Shawn Hall said Wednesday that the latest move by Mason is another tactic to continue their empty voting strategy, which he said allows the firm to turn a profit at the expense of other shareholders.
Telus has accused Mason of empty voting — because it wields voting influence while holding a small economic interest in the company due to its short position — to widen the financial gap between its common and non-voting shares, which had been narrowing.
"New York hedge fund Mason Capital’s use of the controversial empty voting strategy is an affront to shareholder democracy and good corporate governance," he said.
"Any comments or allegations they make should be viewed as self-interested, so they can exit their hedge position in Telus without incurring a loss."
He added that Telus will oppose the filing, but said the company could not comment further because the issue is before the courts.
Shares in Telus lost $1.01 to close at $62.23 on Wednesday.