Monday was a great day on Wall Street, as major market benchmarks started the second quarter on the same positive footing they had throughout the first quarter. Most stock indexes were up 1% or more as investors were optimistic about the prospects for global economic growth remaining strong, especially in key areas like China. Good news about certain companies also helped sentiment. Wynn Resorts (WYNN -5.50%), Advaxis (ADXS 19.82%), and Roku (ROKU -1.70%) were among the top performers. Here's why they did so well.

Wynn looks to win in Macau

Shares of Wynn Resorts gained more than 8% after investors in the casino resort giant heard the latest numbers from the overseer of casino gaming activity in Macau. The Gaming Inspection and Coordination Bureau said that gaming-related revenue in March fell 0.4% from year-ago levels to about $3.2 billion, but the number was higher than February's total and was better than most investors had expected. Wynn shareholders had been especially concerned at recent signs of Chinese economic weakness, fearing that it could spill over into Macau. But with renewed optimism, Wynn remains poised to benefit as long as the Asian gaming capital remains strong.

Wynn hotel with lighted fountains in front.

Image source: Wynn Resorts.

Advaxis hopes for a new cancer fighter

Advaxis stock picked up 10% following the release of key findings from a phase 1/2 trial of the biotech's ADXS-PSA treatment for a type of prostate cancer. The study involves evaluating ADXS-PSA both on its own and in combination with Merck's Keytruda, and some of the more encouraging findings thus far include reasonably good tolerance of the drug, prolonged survival data, and signs of interactions with patient immune systems. Advaxis believes the data thus far support continued study, and investors hope that after years of struggles, the final news will eventually be good for ADXS-PSA and Advaxis as a whole.

Roku shows a pretty picture

Finally, shares of Roku rose 7%. The streaming platform specialist got favorable comments from analysts at KeyBanc Capital Markets, who boosted their target price on the stock by $13 to $76 per share. Despite some worries among shareholders about rising levels of competition in the industry from the largest of tech giants, KeyBanc doesn't have major concerns about Roku's platform, which benefits from a significant first-mover advantage and proven demand. Even with the stock having more than doubled to start 2019, Roku could have further to run, and investors are buying into the bullish case for the company.