Does The Fall In MasTec Stock Change Anything?
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Between May 8 and November 4, 2026, MasTec (MTZ) stock fell 59.5%. The S&P 500 returned 4.5% over the same period. MasTec’s two worst days were July 31, right after its second-quarter report, when it fell 18.9%, and November 4, when it fell 15.4% as AI data center stocks slid after the Democrats’ midterm election sweep. On the October 30 earnings call, management described near-term challenges in the Pipeline and Communications businesses. The price appears to assume that MasTec’s growth is now worth far less than investors thought in May. Is MasTec earning less on its work, or winning less of it?
MasTec’s Third-Quarter Profit Fell As Sales Grew
In the quarter ended September 30, 2026, sales at MasTec rose 29.9% from a year earlier. That growth includes partial-quarter results from The Superior Group, which MasTec bought in July. Yet net income fell to $151 million from $161 million. Operating profit still climbed to $263 million from $250 million. But interest expense rose to $62 million from $45 million, more than offsetting that gain. The operating margin, the share of sales remaining after the costs of the work and of running the company, slipped to 5.1% from 6.3%.
Management attributed part of the weaker profit to project timing in the Pipeline business. During the October 30 call, executives said several awarded projects started about 60 days late, mostly because of permits. These delays hurt the third quarter and will affect the fourth. Management also lowered its 2026 outlook for adjusted EBITDA, its preferred profit measure, to a range of $1.56 billion to $1.60 billion. Management added that the late starts have very little impact on the projects’ expected profitability, and that work not finished in 2026 will be done in 2027.
Over twelve months, MasTec’s operating margin still rose to 4.9% from 4.2% a year earlier. So far, the thinner margin has appeared in one quarter.
How Expensive Was MasTec Stock Before The Fall?
The shares were very expensive by the company’s own history. At the end of June 2026, MasTec stock sold for 2.0 times its sales over the prior twelve months, marking its highest multiple at any quarter end from the close of 2016 through September 2026. By the November 4 close, the stock sold for 0.77 times. Peers shared part of the fall. Between May 8 and November 4, EMCOR fell 31% and AECOM 14.6%, while APi was flat. MasTec lost about twice as much as EMCOR.
Valued on profit, MasTec stock still costs more than the broader market, trading at 27.4 times its last twelve months’ earnings against 22.8 for the S&P 500. If net income keeps falling while sales grow, as it did in the third quarter, you would be paying that higher multiple for profit that is not keeping up with sales.
Is MasTec Winning Less Work?
No. Excluding acquired businesses, MasTec took in new orders worth 1.3 times the work it billed in the third quarter, so its order book kept growing from its own sales effort.
Communications sales are the weak spot. Management said that business has fallen to just under 15% of MasTec’s revenue so far in the second half of 2026. If it were guiding today, management added, it would call for a flattish 2027 there, with better margins.
MasTec’s margin slipped in the latest quarter, but its order book did not. Backlog, the work MasTec has won but not yet done, reached a record $24.5 billion at the end of September, standing more than $7 billion above a year earlier. About $1.8 billion of that total came with The Superior Group, the electrical contractor MasTec bought in July. MasTec’s backlog in its fourth-quarter report, expected in February 2027, is the number to watch.
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