Is it possible to produce candlestick charts in the Numbers app?

With enough effort it can be done

G2 =IF(C2≥B2, IF(C2−B2≤0.01,B2−0.005,B2),0)

H2 =IF(C2≥B2,IF(C2−B2≤0.01,0.01,C2−B2),0)

I2 =IF(B2>C2,IF(B2−C2≤0.01,C2−0.005,C),0)

J2 =IF(B2>C2,IF(B2−C2≤0.01,0.01,B2−C2),0)

K2 =IF(B2<=C2,B2−D2,0)

L2 =IF(B2<=C2,E2−C2,0)

M2 =IF(B2>C2,C2−D2,0)

N2 =IF(B2>C2,E2−B2,0)

Fill down with all to complete the columns

G-J are the four series for a stacked column chart

K-M are for error bars for the daily high and low lines

1. Make a stacked column chart of G-J
2. Click on a bar for the "open low" series, choose "negative only" error bars using "custom values". In the entry field, delete the value that is there then go to the table and select column K (or the range of cells in K you are using for the chart). Click the green checkmark.
3. For series "close high", choose "positive only error bars using "custom values". Choose column L
4. Do steps 2&3 for the other two series using the other two columns in the table for the error bars.
5. Select the error bars for each series (click one, command click the others) then set the bar style to a straight line and the width to 1pt.
6. Select the two series that make the upper part of the columns (by default one is probably blue and the other orange right now). In the Style tab, set the stroke to a line and 1pt.
7. For the candlestick for "opened low and closed high", select the top bar and set the fill to white (or green). Select the bottom bar and set the fill to none.
8. For the candlestick for "opened high, closed low", set the top bar fill to black (or red) and the bottom bar fill to none.
9. Click elsewhere on the chart then go to the "chart" tab. Turn off the legend and select "hidden data".
10. Hide all those extra columns in the table

I hope I got everything in there.

I was able to follow Badunit's instructions for his ingenious solution.

Here's a way to make an avg-high-low chart if your needs are simpler:

SG