The Philippine Stock Exchange Index (PSEi) retreated on Monday, falling 58.97 points or 0.99 percent to 5,879.41, while the peso weakened to P61.69 per US dollar from P61.47 on Friday as renewed military exchanges between the United States and Iran dampened investor sentiment.

Concerns over potential disruptions to Middle East oil supplies pushed crude prices higher and prompted investors to reduce exposure to risk assets. Brent crude rose nearly 3 percent to $95.99 per barrel, while West Texas Intermediate gained more than 3 percent to $93.30 per barrel in Asian trading.

Trading remained subdued, with value turnover reaching P5.57 billion. Foreign investors were net sellers, posting net outflows of P754.31 million.

All major sectors ended lower, led by Mining & Oil, which dropped 4.04 percent. Only six PSEi constituents finished in positive territory. Meralco (MER) was the day's top gainer, rising 1.44 percent to P564.00, while DigiPlus Interactive Corp. (PLUS) was the biggest loser, falling 6.04 percent to P9.96.

Market breadth remained weak, with 123 decliners against 47 advancers.

Meanwhile, the peso depreciated by 22 centavos, or 0.36 percent, to close at P61.69 per dollar. The local currency opened at P61.495, briefly strengthened to P61.48, then weakened throughout the session to an intraday low of P61.735 before settling near that level.

The BAP weighted average rose to P61.668 from P61.507, while the AM and PM weighted averages stood at P61.652 and P61.694, respectively, reflecting sustained demand for dollars.

The peso tracked broader regional currency weakness as investors sought the US dollar as a safe-haven asset amid escalating geopolitical tensions and rising oil prices.