CPKC Short Positions Rise 56% in a Month Before Q3 Results

Short sellers have been adding to positions in CP at an accelerating pace, with short interest rising 56% over the past month to roughly 6 million shares, equal to 0.67% of the free float. That level remains low in absolute terms, but the pace of the build is notable: positions climbed 14% in the past week alone, a sharp acceleration from earlier in the period.

The borrow market tells a story of easy supply rather than squeeze pressure. Availability is extraordinarily loose, with roughly 96 shares available to lend for every one already borrowed, making CPKC one of the most freely borrowable large-cap industrials on the TSX. Cost to borrow ticked up 11% over the week to 0.58%, but that figure remains near the bottom of its range and poses no meaningful friction for short sellers. In short, the lending market is enabling the build rather than constraining it.

The stock has moved in the opposite direction. Canadian Pacific Kansas City climbed 4.3% over the past week to CAD 127.99, outpacing a median gain of around 0.7% for its closest rail peers. CNR added 2.0% over the same period. UNP rose 3.5%. NSC gained 3.2%. Only freight peers including ODFL and SAIA finished the week lower, suggesting the rail subsector itself is bifurcating heading into the reporting season.

The one prior earnings reaction on record shows the stock fell 4.7% in a single session after Q2 results in July 2026, recovering only partially over the following five days. That reaction came alongside a period of tighter borrow conditions than those prevailing now. The current setup is different: short interest has risen sharply in recent weeks but borrow remains abundant, and the stock has held its gains rather than retreating into the print. The Q3 release will therefore test whether the recent price strength reflects genuine operational progress on the KCS integration or simply a broad lift from the rail sector moving into year-end.