AT&T slides as fiber revenue per user weakens

** Shares of telecom firm AT&T T.N fall 6.6% to $21.9

** Stock on track for its lowest level in three months, if losses hold

** Q3 average revenue per user (ARPU) falls 4% due to introductory promotions, bundle discounts for wireless-and-broadband customers and lower-spending customers from newly acquired Lumen Technologies

** Dilution in ARPU can be attributed to telecom cos that could be discounted by uncertainty of future industry structure with the threat of SpaceX competitive entry into the mobile category - Brokerage Citi

** Sector peers T Mobile TMUS.O and Verizon VZ.N declined 2.9% and 3% respectively

** AT&T expects Q4 adj. EBITDA to be impacted by higher marketing and other customer acquisition costs vs last year due to product launch and fiber expansion initiatives - CFO Pascal Desroches

** Including session's move, T and TMUS down 11.8% and 24.6%, respectively, while VZ up 6.1% YTD