Major benchmarks finished mixed on Monday, with most bouncing back from steeper losses early in the session. Signs of weakness in the European economy rattled investors to begin the week, but as the day progressed, market participants seemed to get more comfortable with the prospects for U.S. stocks. Some companies also saw nice moves higher on good news. Endeavour Silver (NYSE:EXK), PriceSmart (NASDAQ:PSMT), and Fastly (NYSE:FSLY) were among the top performers. Here's why they did so well.

Endeavour shines

Shares of Endeavour Silver climbed nearly 10% on a good day for silver mining stocks in general. The price of silver bullion moved higher by almost 4% today, rising back above $18.60 per ounce as ongoing political tensions continue to send some investors looking for safe-haven investments. Endeavour has been volatile lately as it's faced the dual challenges of weaker production volume and higher operating costs. Yet with silver on the rise, Endeavour stands a better chance of being profitable in the long run. That hope is a big part of what drove shares higher today.

Kilo bars of silver stacked on top of each other.

Image source: Getty Images.

PriceSmart gets into the big leagues

Warehouse retailer PriceSmart saw its shares soar 20% after the company got an invitation to a high-profile stock index. S&P Dow Jones Indices said that PriceSmart will join the S&P SmallCap 600 Index, taking the place of the soon-to-be-acquired Finisar. The changes will take effect before the beginning of the session on Thursday, but many investors routinely try to get in ahead of the many index mutual funds and exchange-traded funds whose investment objectives require them to purchase shares of new index components once they're officially added.

Fastly picks up speed

Finally, shares of Fastly rose 9%. The cloud computing specialist's stock has been extremely volatile over the past couple of months, and its big jump in August regained all the ground the it had lost since its May IPO. Cloud-related stocks have experienced a correction recently after a huge upward move for the sector as a whole, and Fastly hasn't been immune to concerns that some of its share-price gains are due more to momentum-based trading strategies than fundamental growth. Yet few dispute that optimizing users' internet experiences will remain important for years to come, and that should support growth for Fastly for the foreseeable future.