It is a technical analysis tool attached from bottom to top in a rising market and from top to bottom in a declining market. The horizontal lines show the Fibonacci Retracement levels (ratios): 0.236, 0.382 and 0.618. The levels serve as potential support and resistance. The ratios are derived by dividing any number in the sequence by:
the next one, 55/89=0.618
the number two places to the right, 55/144=0.382
the number three places to the right, 55/233= 0.236
