Shares of MasTec plunged 7.5% to $311.43 on July 28, extending a brutal week-long slide that has erased roughly $130 per share — or nearly a third of the stock's value — from its 52-week high of $441.43. No fresh headline explains today's drop. Instead, the selloff reflects investors cashing in profits from a monster first-quarter earnings beat while digesting a wave of debt-fueled dealmaking that has dramatically altered MasTec's balance sheet.

  • A Blowout Quarter Set Up a Big Fall — MasTec's Q1 earnings per share of $1.39 crushed the $0.99 consensus by 40%, on revenue of $3.83 billion that topped estimates by over 10%.

Adjusted EBITDA grew 73% year-over-year , and management raised full-year revenue guidance to $17.5 billion. That blowout sent shares surging past $400 in May. But stocks that sprint on good news are especially vulnerable to profit-taking when momentum fades — and this one has faded hard.

  • A $1.65 Billion Deal Adds Opportunity and Debt — MasTec is paying roughly $1.65 billion — $1.175 billion in cash and $475 million in stock — to acquire the Superior Group , a full-service electrical contractor focused on critical infrastructure. To fund it, MasTec on July 20 drew the full $700 million from a new term loan

and another $600 million from its revolving credit facility.

Management says the deal will immediately add to earnings and cash flow , but loading $1.3 billion in new borrowings onto the books gives investors a reason to demand a lower price until integration proves out.

  • Insiders Were Selling Into Strength — Insiders sold $3.7 million worth of shares in the last three months with no buying activity.

MTZ insiders have only sold shares in the past three months. That one-way traffic doesn't necessarily mean trouble, but combined with a stock that had nearly tripled in a year, it gives nervous holders another excuse to hit the sell button.

  • Valuation Was Already Stretched Before the Drop — Analysts project roughly $9.18 in earnings per share for 2026. Even after today's decline to $311, MTZ trades at about 34 times that estimate — a rich price for an infrastructure contractor. Truist has a $550 target , but Zacks recently downgraded the stock to "hold." The tug-of-war between MasTec's record $20.3 billion backlog and its newly leveraged balance sheet will likely define the next chapter.