Shares of American Axle & Manufacturing Holdings Inc. tumbled 10.0% in midday trading Friday, after the auto parts supplier reported a fourth-quarter sales that missed expectations, as results were hurt by a work stoppage at General Motors Corp. , and provided a downbeat outlook. The net loss widened to $454.4 million, or $4.04 a share, from $361.8 million, or $3.24 a share, in the year-ago period. Excluding non-recurring items, such as a $440 million goodwill impairment charge, adjusted earnings per share came to 13 cents, beating the FactSet consensus of breakeven. Sales fell 15.6% to $1.43 billion, below the FactSet consensus of $1.50 billion, with the GM work stoppage reducing results by about $186 million. For 2020, the company expects sales of $5.8 billion to $6.0 billion, below the FactSet consensus of $6.1 billion, with Chief Executive David Dauch saying on the conference call, according to a FactSet transcript, that guidance includes an estimated impact of lower production in China as a result of the coronavirus outbreak of $25 million. That impact assumes production in China resuming over the second half of February and into early March. The company expects 2020 free cash flow of about $300 million, below expectations of $323 million. The stock has shed 37.4% over the past 12 months, while the S&P 500 has gained 22.9%.Market Pulse Stories are Rapid-fire, short news bursts on stocks and markets as they move. Visit MarketWatch.com for more information on this news.