Mirion Short Interest at a One-Year High Ahead of Earnings

MIR is the most crowded name in its immediate peer group as it reports today, with short interest at 18.1% of free float, the highest reading in at least a year. Closest peers AEIS and PLXS trade with no comparable short burden, and the group's median was actually down on the week while MIR edged up 1.1%.

Short interest has climbed steadily through October, rising 8.2% over the past month to 41.4 million shares. ORTEX's short score now registers 74.8, a level that places the stock in the 98th percentile on this measure across the broader universe. Despite that pressure, the borrow market tells a calmer story. Availability is running at 190%, meaning roughly twice as many shares are available to lend as are already borrowed, well within normal territory. Cost to borrow has crept higher over the past month, up about 21% to 0.56%, but that is still a negligible rate for a name with this level of short interest. The two signals diverge: positioning is heavy, but the infrastructure to cover quickly is there.

The analyst community remains constructively positioned, with the mean price target at $24, implying roughly 56% upside from the current $15.41. Most of that target-setting took place after the July earnings release, when Citigroup, Goldman Sachs, and several others trimmed numbers but held positive ratings. Jefferies initiated with a Buy and a $20 target in early September. Morgan Stanley sits as the lone sceptic with an Equal-Weight. The debate centres on two conflicting data points: EBITDA margins that have expanded meaningfully, supported by strong Nuclear Power segment revenue, set against a backlog that has struggled to grow. A backlog reading of $814 million at the start of 2025 showed only marginal sequential improvement and a year-on-year decline, and that tension has not been resolved publicly since.

Wikipedia attention for MIR is running at a z-score of 3.4 against its own prior 90 days, a sharp spike in retail interest on the day of the print. That is a reflection of attention, not a revenue signal, but it captures the elevated stakes around today's release.

The print will test whether margin expansion has continued without backlog recovery, and whether that trade-off is one the market is willing to accept at a stock still priced well below where most analysts set their targets.