TWX market cap is about $57B. Time Inc. is worth about $2B. so about 3% of the value of TWX will be spun off into Time Inc. entity. if it goes like the AOL spinoff you'll get 1 Time Inc. share for every 11 TWX shares you own. there are lots of other factors involved - share amounts, shares outstanding, dividends etc. so this is just a rough guideline. my guess is TWX will fall about $1-2 at the spinoff - all other things being equal.