Short answer. The court decides the amount. Section 13 requires the court to allow the commissioner reasonable compensation as the circumstances of the case warrant, and that compensation is then taxed as costs against the defeated party, or apportioned between the parties as justice requires.
What the law says
The court shall allow the commissioner such reasonable compensation as the circumstances of the case warrant, to be taxed as costs against the defeated party, or apportioned, as justice requires.
Rule 32, Section 13 — Compensation of commissioner. Read the full provision →
The court fixes the amount
Rather than leaving the commissioner or the parties to negotiate a fee among themselves, the court alone sets 'reasonable compensation' based on the circumstances of the particular case. Leaving the amount to the court, rather than to negotiation between the commissioner and one or more parties, avoids the obvious conflict of interest that would arise if the commissioner's pay depended on the goodwill of the very parties whose dispute the commissioner is supposed to handle impartially and fairly for both sides. A commissioner who instead had to negotiate a fee directly with the litigants would have an obvious incentive to favor whichever side seemed more willing to pay generously, undermining the very impartiality the commissioner is appointed to bring to the case.
Who ultimately pays
The default approach is that compensation is taxed as costs against the party who loses the case, following the general and long-standing principle that the losing party normally bears litigation costs. Treating the commissioner's fee as an ordinary item of costs means it gets resolved through the same mechanism as filing fees and other litigation expenses, rather than through some separate, freestanding payment process. This also discourages parties from unnecessarily prolonging proceedings that require a commissioner's involvement, since the losing side ultimately absorbs that added expense along with everything else in the end. Folding the fee into ordinary costs, rather than requiring a separate payment order, also spares the parties an extra layer of litigation just over how the commissioner gets paid.
The apportionment alternative
Where taxing the full cost to the defeated party wouldn't be just, the court can instead apportion the compensation between the parties as justice requires, giving it flexibility beyond a rigid winner-pays rule. A case where both sides contributed to the need for a commissioner, or where the outcome was mixed rather than a clean win for either side, is the kind of situation where apportionment makes more sense than a straightforward loser-pays approach. This discretion lets the court fit the cost allocation to the actual dynamics of the dispute, rather than defaulting mechanically to whichever single party technically lost the case overall.