Very Weird missing bitcoin problem.--SOLVED

[Room101]

Ok so this is a strange one, not sure if i have missed something obvious but here it is:

3 days ago I was sending a few bitcoins through blockchain.info send shared and of the 5 or 6 transactions i sent, one of them was taking a long time to arrive. I wanted to buy something so I went ahead and bought it from the wallet the coins were going to be sent to. The last sendshared (3.81BTC) never arrived......BUT the last transaction, the one i spent, was for 18.1 BTC. However when i search blockchain.info, it shows that last transaction as being for 14.23BTC NOT the 18.1BTC i sent. Now if you add the missing 3.81 to the 14.23 blockchain has as outgoing, you get 18.1BTC (including fees etc). The thing is though, the wallet in question shows 18.1 BTC as the outgoing transaction??? So what my wallet says and what blockchain.info says do not measure up. I sent 18.1, but it seems somehow blockchain is saying i only sent 14.2, then it added the 3.81 i was supposed to get through sendshared, yet the full 18.1BTC is gone from my wallet!! Basically i am out that 3.81BTC, and would really like to know where the hell it has gone.

Any suggestions, have contacted customer support with blockchain.info but no reply in the last 48hrs.

[suryc]

The point of shared send is that you won't be able to trace the transaction on blockchain.info by looking at the transactions and they may break it up into different pieces. It mixes your btc with others and provides some additional anonymity.
Full explanation here:
https://blockchain.info/wallet/send-shared

Look at the address(es) that you sent to and see how much was received. That total will be the same as what left your wallet, but it might be in different increments.

Also, shared send can take a long time to be received. Sometimes people have reported as much as 48 hours.
The only reason to use shared send is if you want to make the transaction a little bit more anonymous.

[BurtW]

If you care to share some of the addresses involved either here or by PM we can research it for you.  However if you want to be anon that may not be a good idea

[BurtW]

He sent me the address in question.  When he sent out the 18.0 from his wallet then only 14.2 were available on the one address he is looking at in blockchain.info.  All of these were sent.  This was not enough for the transaction so the wallet, by design, picked up the needed coins from another address.

The rest of the coins needed for the transaction ( 18.0 - 14.2 = 3.8 ) were actually sent by sending 4.7 from another one of the addresses in his wallet.  He then got 4.7 - 3.8 = 0.9 in change back to a totally different address in his wallet.  (All amounts rounded off to the nearest 0.1)

So at least that part of the mystery is solved:  You did sent 18.0 total out of your wallet in the following transaction 14.2 + 4.7 - 18.0 = 0.9 change back.

EDITED for numerical accuracy.

[BurtW]

Bottom line lesson from this misunderstanding is:

Bitcoin Wallet =/= A Bitcoin Address

In fact:

Bitcoin Wallet == A collection of many Bitcoin Addresses

[Room101]

Thanks for the help everyone, clearly i need to keep better records.