Summary

1029 obs. Since two duplicates in 1032 and one error (same target name, same parent name, same announcement date, but one week difference in the effective date. These two should be the same spinoff event.)

902 spinoffs with public parents. 772 obs with complete cusip/permn match

Process:

1. merge_20140529.SAS => Mainly merge Cusip with CRSP (Permnos)

2. Clear v1.SAS => Mainly merge above with Compustat (Gvkey)

3. Final2.SAS => Event study on the spinoff announcement date

4. Final3.SAS => Event study on the management forecast date

5. Compustat_Firm_Characters => ROA, BM, Leverage of parent firms pre & post-spinoffs

6. list_20140613.SAS => I list target firms with public status and chech whether those firms are active before spinoffs. I start with 181 obs. 91 are active. 66 are inactive, which have less than 15 daily CRSP obs in the previous month of spinoffs. The remaining ones are lack of permnos.

7. permno_gvkey macth_20140613.SAS => permno and gvkey should be 100% match. If not, find a reason. So far, 4 out of 506 target_permnos cannot be matached with a gvkey. 7 out of 772 parent_permnos have missing gvkeys.

8. Program20140718 => Merge SDC with IBES by 6-digit CUSIP

9. Program20140722 => Merge SDC with COMPUSTAT by 6-digit CUSIP
9a. Try to find a closest control group
9b. Same 2-digit SIC / 30% Assets / Closest MB ratio

10. manual 20140804 (3).xlsx 是一个重要的文件！我花了500年时间在上面！校对了很多SDC的spin off的母公司和子公司，以及他们的Permno和GVKEY。里面有全系列的a2,b1,b2,c1,c2,d1,d2。和部分a1，如果spin off当日，母公司的RET呈现missing状态。

11. munual_check.SAS => 这个有校对了一下上面的manual 20140804 (3).xlsx有没有漏信息，漏了两个，已经补齐。所以只需看manual 20140804 (3).xlsx即可.

12. SDC_permno_withdup3是从Program20140725来的。Program20140725是一个新的merge。从SDC到CRSP，通过四种不同的方式merge。

第一步，用6-digit CUSIP和time.
第二步，放宽条件，不要求Time也对。
第三步，用Immediate parent cusip，无关time。
第四步，用Ticker.
第五步，手动查找Missing obs。

看这个链接，关于这几步的详细分解。
http://accandfin.blogspot.com/2014/08/data-summary.html

13. AllInOne现在是最牛逼的文件了。1029个SDC过来的spin off都被手动找了一遍。