Business Performance: Embraer's (EMBYF.US) financial health, including revenue, profitability, and order backlog, significantly influences its stock price. Strong earnings reports typically lead to price increases.

Industry Trends: The overall state of the aerospace and defense industries affects EMBYF.US. Factors like increased air travel demand or government defense spending can positively impact the stock.

Economic Conditions: Global economic growth or recessionary periods influence demand for aircraft and related services, impacting Embraer's prospects and stock price.

Government Regulations: Changes in aviation regulations or trade policies can significantly affect Embraer's operations and stock valuation.

Competition: The competitive landscape, including the performance of rivals like Boeing and Airbus, influences investor sentiment and Embraer's market share, thereby impacting its stock.

Currency Exchange Rates: As a Brazilian company, Embraer's financials are affected by fluctuations in the Brazilian Real against the US Dollar, which can impact its reported earnings and stock price.

Geopolitical Events: Global political instability or conflicts can affect the aerospace and defense sectors, potentially impacting Embraer's stock.

Investor Sentiment: Market optimism or pessimism regarding Embraer's future prospects, driven by news and analyst ratings, can cause short-term price fluctuations.