The most common and most likely answer to this crossword clue is the 8 letter word STRADDLE
I've seen this crossword clue in Financial Times
S
T
R
A
D
D
L
E
More clues leading to the result STRADDLE
- Put pins around seat covers tailor's edging
- Go across the range initially in area between peaks
- Go across street with right turn
- Small daughters inside ground later sit on the fence
- Celebrated instrument led off — it’s what cellists do
- In her seat, the rider initially will do this!
- Turn red, stumped by rising stock transaction
- Appear to favour both sides of violin
- Lumber covers frame of timber for bridge
- Fiddle next to valley, cutting a hedge
Buddy explains!

The straight part
We know that "sit on the fence" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sit on the fence = straddle.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does STRADDLE mean?
STRADDLE noun- A posture in which one straddles something.
- An investment strategy involving simultaneous trade with put and call options on same security with positions that offset one another.
- A voluntary raise made prior to receiving cards by the first player after the blinds.
- A vertical mine-timber supporting a set.
- To sit or stand with a leg on each side of something; to sit astride.
- To be on both sides of something; to have parts that are in different places, regions, etc.
- To consider or favor two apparently opposite sides; to be noncommittal.
- To form a disorderly sprawl; to spread out irregularly.
- To fire successive artillery shots in front of and behind of a target, especially in order to determine its range (the term "bracket" is often used instead).
- To place a voluntary raise prior to receiving cards (only by the first player after the blinds).
- To stand with the ends staggered; said of the spokes of a wagon wheel where they join the hub.
- To execute a commodities market spread.
- Astride.