The Dow Jones industrial average fell 171 points in Thursday trading to close at 17,906.

The S&P 500 fell 18 points to 2,096.

The Nasdaq fell 40 points to 5,059.

The LABJ Stock Index fell one point to 232.

Gainers and Losers

Thursday’s biggest local gainer was Internet advertising company ReachLocal Inc.

Shares rose 7 percent on the day, closing at $3.10. The Woodland Hills company last month introduced a mobile app that delivers location-based advertising to mobile phones.

Thursday’s biggest loser was semiconductor manufacturer Trio Tech International. The Van Nuys company’s shares fell 6 percent on the day, closing at $3.11.