Many investors pay attention to mid-cap stocks because they have established business models and expansive market opportunities. However, their paths to becoming $100 billion corporations are ripe with competition, ranging from giants with vast resources to agile upstarts eager to disrupt the status quo.

Luckily for you, our mission at StockStory is to help you make money and avoid losses by sorting the winners from the losers. Keeping that in mind, here are two mid-cap stocks with long growth runways and one that may have trouble.

One Mid-Cap Stock to Sell:

TopBuild (BLD)

Market Cap: $11.37 billion

Established in 2015 following a spinoff from Masco Corporation, TopBuild (NYSE: BLD) is a distributor and installer of insulation and other building products.

Why Do We Think Twice About BLD?

1. Products and services are facing end-market challenges during this cycle, as seen in its flat sales over the last two years
2. Organic sales performance over the past two years indicates the company may need to make strategic adjustments or rely on M&A to catalyze faster growth
3. Earnings growth underperformed the sector average over the last two years as its EPS grew by just 2.5% annually

TopBuild’s stock price of $407.28 implies a valuation ratio of 19.7x forward P/E. Check out our free in-depth research report to learn more about why BLD doesn’t pass our bar.

Two Mid-Cap Stocks to Buy:

Samsara (IOT)

Market Cap: $20.09 billion

From sensors on vehicles to AI-powered cameras that help prevent accidents, Samsara (NYSE: IOT) is a cloud-based Internet of Things platform that helps businesses improve the safety, efficiency, and sustainability of their physical operations.

Why Is IOT a Top Pick?

1. Customers view its software as mission-critical to their operations as its ARR has averaged 31.8% growth over the last year
2. Forecasted revenue growth of 21.2% for the next 12 months indicates its momentum over the last two years is sustainable
3. User-friendly software enables clients to ramp up spending quickly, leading to the speedy recovery of customer acquisition costs

Samsara is trading at $34.85 per share, or 11.6x forward price-to-sales. Is now a good time to buy? See for yourself in our in-depth research report, it’s free for active Edge members.

W. R. Berkley (WRB)

Market Cap: $29.38 billion

Founded in 1967 and operating through more than 50 specialized insurance units across the globe, W. R. Berkley (NYSE: WRB) underwrites commercial insurance and reinsurance through specialized subsidiaries serving industries from healthcare to construction to transportation.

Why Will WRB Outperform?

1. Net premiums earned expanded by 12.4% annually over the last five years, demonstrating exceptional market penetration this cycle
2. Share repurchases have amplified shareholder returns as its annual earnings per share growth of 35.5% exceeded its revenue gains over the last five years
3. Expected book value per share growth of 20.3% for the next year suggests its capital position will strengthen considerably

At $77.30 per share, W. R. Berkley trades at 2.9x forward P/B. Is now the right time to buy? Find out in our full research report, it’s free for active Edge members.

Stocks We Like Even More

Your portfolio can’t afford to be based on yesterday’s story. The risk in a handful of heavily crowded stocks is rising daily.

The names generating the next wave of massive growth are right here in our Top 6 Stocks for this week. This is a curated list of our High Quality stocks that have generated a market-beating return of 244% over the last five years (as of June 30, 2025).

Stocks that made our list in 2020 include now familiar names such as Nvidia (+1,326% between June 2020 and June 2025) as well as under-the-radar businesses like the once-micro-cap company Tecnoglass (+1,754% five-year return). Find your next big winner with StockStory today for free. Find your next big winner with StockStory today. Find your next big winner with StockStory today

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