Form 593-'x' (A, B, or C, I think - usually A) is generally(*) completed on real estate sales in CA.   This tells the title escrow Company how much to withhold.  The computation is 3.333% of the selling price  OR  12.3 % of the 'gain'.   Obviously, the 'gain' can be manipulated (altho there is a computation part of the form to list cost + improv etc).

IF the title/escrow Company was told there's no gain, OR if told it was a primary residence with the @ 250/$ 500,000 box checked - there wouldn't be any withholding.

@katie  - this Form 593 is often/usually buried deep in the 3# stack of closing papers.  The amount WILL show on the closing/HUD statement tho as "FTB withholding".  A call to the title Company (probably with someone on the closing statement for authorization) might be in order IF there is an amount on the closing statement but the F.593 is MIA.

(*) I say generally because I just went thru this with a local small town title Company (a franchise) that messed up the F.593 so badly it's funny/sad?