AMX B Post-Earnings: The Rebuild That Wasn't

América Móvil has just reported Q3 results, and the week's most telling detail is what didn't happen: the short rebuild that dominated the pre-earnings narrative has now fully stalled, while the stock itself quietly added nearly 6% on the week.

The positioning picture has shifted materially from what the two most recent previews described. As of October 19, short interest stood at 6.52 million shares, up just 2% on the week after the 7.6% weekly gain flagged in the October 17 note. More telling is the month-on-month direction: shorts are down 20% from a month ago, and the mid-September peak of roughly 8.7 million shares has not been challenged. Short interest as a percentage of the free float remains low enough that it is not a meaningful driver of price action here. The borrow market reinforces that reading. Availability has loosened sharply over the past month, running at 5,769% of short interest on October 20, well above the 52-week low of 1,093%, meaning there is no scarcity of shares to borrow. Cost to borrow at 0.93% ticked up 6% on the week but remains firmly in low territory, ranging between roughly 0.80% and 0.95% for most of the past three months. The lending market is telling you that short sellers face no friction whatsoever, and few are choosing to use it.

The earnings event itself landed on October 21 with minimal warning: the announcement was only flagged on October 6, and the snapshot carries no price-reaction data for today's print yet. What is clear is that the stock arrived at the event in good shape. AMX B closed at MXN 21.07 on October 20, up 5.9% on the week and 8.6% on the month. That is a notably better run-in than the September lows would have suggested. The one prior quarterly result in the history with a reaction figure showed a 2.8% gain on the day and 7.4% over the following five days, from the October 13 print, suggesting the market has recently been willing to reward results. The next scheduled event is now February 9, 2027.

One structural fact about ownership is worth flagging. A Schedule 13D/A filing from December 2024 shows Marco Antonio Slim Domit disclosing a 51% stake in América Móvil at that time. This is an activist-classified filing under SEC definitions, though for a company of this structure, a controlling family shareholder holding above 50% is better understood as a governance feature than a campaign. The caveat applies in full: 13D/G stakes are as-last-disclosed around the 5% threshold, and the filing is now over 18 months old. The CFO, Carlos Jose Garcia Moreno Elizondo, exercised options in August for a combined 952,000 shares across three tranches at prices between MXN 1.05 and MXN 1.15. At a current price of MXN 21.07, the option strike prices look strikingly low, which likely reflects the ADR versus local-share conversion rather than a pricing anomaly. These were coded as transaction type X (option exercises), not open-market purchases, and carry a significance score of 1, meaning they do not read as conviction signals.

Among correlated peers, Tele2 gained 5.5% on the week and MTN Group added 4.3%, so AMX B's 5.9% weekly move looks broadly in line with a rising tide in global emerging-market telecoms rather than a company-specific re-rating. TIGO was essentially flat on the week at 0.3%, the one notable laggard in the group.

With results now in and the next event four months away, attention turns to whether the short rebuild seen through September and into early October resumes, or whether today's print gives short sellers further reason to stand aside.