The event is Spain's auction of 10-year government bonds (Obligaciones del Estado), a key indicator of the country's borrowing costs and investor confidence. The Spanish Treasury sets an issuance target, and the yield is determined by competitive bidding among banks and investors. Strong demand or higher yields can signal market sentiment toward Spain's fiscal health, impacting the euro and European bond markets. Traders watch for changes in yield and bid-to-cover ratios as signals of risk appetite or stress. Historically, Spanish bond auctions have influenced EUR/USD volatility, especially during periods of eurozone debt concerns.