Can I report Short Term transactions not reported to the IRS on the 1099-B as "Short Term non covered" or "Short Term" not reported"? Where is the 8949?

[weheyd]

Your 1099-B should specify whether a short term transaction is Form 8949 Type A (basis reported to the IRS) or Form 8949 Type B (basis not reported to the IRS) or Form 8949Type C (Form 1099-B not received).  In my limited experience with Form 8949 Type C (Form 1099-B not received), I found the tax treatment to be significantly less favorable for a Form 8949 Type C (Form 1099-B not received) transaction.  Therefore it is best to use Form 8949 Type C only when it fits your fact situation.  If you did not receive a Form 1099-B for a transaction, but believe you should have, you should request the relevant Form 1099-B from your broker or other entity.

For information, the analogous Long Term Types are Form 8949 Types D, E, and F, respectively.  The same considerations exist for Type F as described above for Type C.

[fanfare]

you must file your transactions under the proper category if you don't want a letter from the IRS asking you what's going on.

[fanfare]

regardless of category, a Form 8949 will be generated if you enter transactions individually.