Apple slips on Q1 gross margin, services growth forecast
** Shares of iPhone maker Apple AAPL.O fall 4.1% to $324.5 in extended trading after co reports fourth-quarter results
** On post-earnings call, Apple says it expects services revenue to grow between 8% and 9% in Q1
** Company forecasts Q1 gross margin of 45% to 46%; CFO says outlook includes the impact of higher memory chip costs and spending related to Siri AI
** Co reports Q4 revenue of $114.48 bln, above analysts' average estimate of $113.39 bln, according to LSEG data
** Quarterly profit per share of $2.10 beat estimates of $1.99
** Co reported Greater China revenue rise of $17.54 bln from $14.49 bln a year earlier, compared with estimates of about $18.58 bln
** Up to last close, stock has risen ~25% this year