For long-term investors, tapping into big trends can be a way to turn even relatively small sums into much bigger amounts over time. If you've got your financial bases covered and have $1,000 available to safely invest, read on to see why investing $500 in each of these two growth stocks could be a smart move. 

1. Taiwan Semiconductor Manufacturing

When Nvidia, Apple, and other tech leaders need their high-performance chip designs manufactured, they turn to Taiwan Semiconductor Manufacturing (TSM -0.73%). The industry leader actually pioneered the dedicated-foundry business model, and it remains the largest contract chip fabricator by far. While second-place fab company Samsung and third-place player Intel also have substantial foundry capabilities, they also have their own specialties, design initiatives, and ambitions. 

By contracting through TSMC, customers can rest assured that the company will keep the privacy of its designs under wraps and not attempt to integrate them into its own business plans. What's more, TSMC has earned a fantastic reputation when it comes to low chip failure rates and delivering semiconductors to customers on time. 

Within the global contract manufacturing market for semiconductors, TSMC currently has greater than 60% market share. For high-performance chips used for artificial intelligence (AI) and accelerated computing processes, the company is actually capturing more than 90% of the contract manufacturing market.

While macroeconomic headwinds and some cyclical downturn have caused the company's sales to decline this year, rising sales contribution from the high-end chip category has helped to boost the company's already impressive margins. In the second quarter, TSMC posted a gross margin of 54.1%, an operating income margin of 42%, and a net profit margin of 37.8%. 

TSM PE Ratio (Forward) Chart

TSM PE Ratio (Forward) data by YCharts

TSMC's business is hugely profitable, and the company will continue to play a leading role in creating hardware that powers this century's biggest tech trends. With the stock trading at roughly 17 times this year's expected earnings and paying a dividend that yields 2.1%, shares are a worthwhile buy right now. 

2. Roblox

Roblox (RBLX -0.81%) stands as an early leader in the metaverse space and is already seeing encouraging levels of engagement and monetization. In the second quarter, the company's average daily active users (DAUs) rose 25% year over year to reach 65.5 million. Powered by rising sales for its virtual world's currency, bookings rose 22% to reach $780.7 million. 

Roblox is already on track to generate well over $3 billion in bookings this year, but the company has just started to pull a new monetization lever. Digital advertisements are being integrated into the platform, and this new revenue source will likely wind up being a major performance driver for the company. 

In terms of age demographics on the platform, Roblox continues to see encouraging progress in aging up. DAUs in the 13-and-up age category increased 33% year over year, and the DAU count in the 17-to-24 age demographic climbed 36% compared to the prior-year period. Aging up is an important, positive trend for Roblox because it allows the company to serve a wider audience, reach users with higher levels of disposable income, and lay the foundations for a much more valuable in-platform advertising network.

In addition to its emerging advertising opportunity, Roblox's potential in AI remains underappreciated. While applications including OpenAI's ChatGPT took the world by storm in short order, it's worth keeping in mind that adoption and per-user engagement for generative AI services remains in its infancy. Roblox's young and highly engaged user base could make the platform a launching pad for a new group of generative AI users. The company has already rolled out virtual-item creation and coding assistance tools for creators on its platform, and artificial intelligence integration is likely just getting started.

Roblox is already serving up strong growth, and the business appears to be on the verge of some powerful new performance catalysts. Still down 81% from its high, the stock looks like a great buy-and-hold play for growth-focused investors.