Jan. 24 (Bloomberg) — U.S. stocks fell Friday, pushing the Dow Jones Industrial Average toward the biggest weekly decline since May 2012, as a selloff in developing-nation currencies spurred concern global markets will become more volatile.

Caterpillar Inc., General Electric Co. and Boeing Co. slid at least 2.7 percent to lead losses in the Dow. Kansas City Southern plunged 15 percent, the biggest retreat since 2008, after reporting lower-than-estimated earnings. International Game Technology tumbled 14 percent as the maker of slot machines posted first-quarter profit that missed analysts' projections.

The Standard & Poor's 500 Index retreated 1.8 percent to 1,795.25 at 3:30 p.m. in New York for its biggest drop since June. The benchmark index has declined 2.4 percent this week to the lowest since Dec. 13. The Dow slid 262.07 points, or 1.6 percent, to 15,935.28 today. The 30-stock gauge is down 3.2 percent this week. Trading in S&P 500 stocks was 53 percent above the 30-day average at this time of day.