the person who beat the company to an untapped market = the person who discovered a new market before the company did. An untapped market is a product or service that has the potential to yield a handsome profit. In the example below, "yellow-fleshed potatoes" that were disease-resistant weren't sold in the US until someone discovered a way to grow them.

Yukon gold potato history
Yellow-fleshed potatoes are common in Europe and South America. In fact, yellow flesh potatoes are actually considered the norm in most countries outside North America, so naturally, immigrants to North America were accustomed to and preferred potatoes with yellow flesh. This untapped market was begging for an enhanced, disease-resistant gold variety easily grown in North America.
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