Hammond Power Solutions (TSX:HPS.A) jumped C$19.83 to close at C$207.75 on Monday, November 9, one of the biggest gains on the S&P/TSX Composite that day. The company issued no new announcement. The bounce came as investors bought back into stocks tied to AI data centres after last week's sell-off, while industrials helped push the index to its highest close since early September.

What happened

The Guelph, Ontario-based transformer maker finished the day up C$19.83 from Friday's close of about C$187.92. It was the top gainer on the S&P/TSX Composite, ahead of Energy Fuels, Silvercorp Metals and Hudbay Minerals.

The most recent company news was its third-quarter report on October 29. Analyst target changes came in the first days of November, including a cut from RBC, so they came before this move.

That leaves the market backdrop. The S&P/TSX Composite rose about 657 points to 36,446.26, with base metals, industrials and financials leading. In New York, the S&P 500 had its best day since April. AMD and CoreWeave, both closely tied to the data centre build-out, won back a large share of last week's losses.

Why it matters

Hammond has become one of the TSX's best-known ways to bet on data centres and the electrical grid. Its dry-type transformers and related gear sit inside the power systems that feed server halls, factories and utilities.

That made it vulnerable when the AI trade cooled. Last week's big drop on Wall Street was driven by fears that Democratic gains in the U.S. midterms could slow data centre construction, since voters have blamed the facilities for higher power bills. Higher borrowing costs had also raised doubts about future projects.

Hammond's stock had already been sliding. It closed at C$308.11 on October 9 and had lost close to two-fifths of that value by last Friday. On Monday, buyers came back to the AI infrastructure trade, and Hammond, after falling that far, had plenty of room to rebound.

The bigger picture

The Business itself looks strong. In the quarter to September 26, sales more than doubled to C$446.3 million from C$218.3 million a year earlier. Adjusted Earnings Per Share came in at C$3.13, up from C$1.56. Cash from operations was C$76.1 million, compared with a small outflow a year earlier.

It was also the first full quarter with AEG Power Solutions, which Hammond bought on June 29, 2026. That deal explains part of the jump in sales. The company said its Power Magnetics Backlog grew sharply from a year earlier, a sign that Demand is holding up.

So the recent swings say less about Hammond's operations than about how investors feel about AI spending, U.S. politics and interest rates. Monday was a strong risk-on day: oil fell after U.S. President Donald Trump said further strikes on Iran were unlikely if peace talks progressed, and that eased Inflation worries.

What to watch next

The key question is whether Monday was the start of a recovery or a one-day relief rally. Watch for policy signals from Washington on data centre power use, and for any shift in the plans of the big cloud companies that drive demand for Hammond's products.

Interest rates matter too. A Bank of Canada survey of Market Participants points to a rate hike in December, and U.S. Treasury yields remain high. Expensive borrowing can delay large construction projects.

Finally, watch how fast the AEG business is folded into Hammond and whether the backlog keeps turning into shipments. Strong order numbers have been the company's best defence against the market's mood swings.