US STOCKS-Wall St falls; Valeant, healthcare drop
* Valeant sinks after Citron report, drags Allergan
* GM, Boeing rise after strong results
* Ferrari up on debut
* Dow down 0.3 pct, S&P down 0.6 pct, Nasdaq down 0.8 pct (Updates to close)
By Caroline Valetkevitch
Oct 21 (Reuters) - U.S. stocks fell on Wednesday as a sharp drop in Valeant Pharmaceutical hit the healthcare space, while the energy sector dropped along with oil prices.
Adding to the negative tone, Yahoo shares fell 5.2 percent to $31.12, a day after the Internet company's quarterly earnings and profit missed expectations.
Valeant Pharmaceutical's U.S.-listed shares sank to an intraday low of $88.50 on record volume, losing about $9.6 billion in market capitalization, after short-seller Citron Research released a report critical about the company.
The stock later pared losses after investor Bill Ackman said he increased his Valeant stake on Wednesday by about 2 million shares. The stock ended down 19.2 percent at $118.61, its lowest level since October 2014. Continuación...