Bitcoin Forum

What type of transaction is this?

e.g.

bitcoin addres 1 (1 BTC - Output)
bitcoin addres 1 (2 BTC - Output)
bitcoin addres 1 (3 BTC - Output)   >>>>> bitcoin address 2 (receiver) (Spent)   7,9999 BTC
bitcoin addres 1 (1 BTC - Output)
bitcoin addres 1 (2 BTC - Output)

I've seen on the left side many different addresses sending to one addresses but I've seen never the same addresses at the sender side.
ps: I'm not a blockchain pro  :o

Each line on the left side is an "output" of a previous transaction.

For example, if an address previously received bitcoins in 10 different transactions, then when sending from that address, the bitcoins come from enough of the 10 "outputs" to cover the amount. If all the bitcoins held by the address are sent, then all 10 outputs will be used and you will see the address listed 10 times.

Just a regular bitcoin transaction.  There is nothing special or unusual about it.

I would say there is something odd. Why are there two outputs to the same address?

Because a ridiculous number of people choose to reduce their own security and the privacy of everyone they transact with by re-using addresses.

Note that the notion of sender addresses (https://en.bitcoin.it/wiki/From_address) doesn't correspond to anything in the protocol, and is potentially quite dangerous. This misunderstanding has led to loss of funds in the past.

When pool mining was still a new thing, miners gave the pool a single payout key.  When the pool got a block, it would then turn around and make a transaction splitting up the block subsidy between all the keys according to the corresponding miner's share.  Thus, a lot of keys received funds in hundreds of different transactions.  But the software got better, and these days pools use a new key every time.

If one of those miners who was sent coins at the same key but in many different transactions were consolidating all those near-dust txOuts into a single, easily-spendable output, the block chain transaction would look exactly like this.  Except, you know, for the amount.  This was a huge transaction. 

This looks more like someone gave a bunch of different investors all the same payment key, got funds from each one in separate transactions, and is making a tx to capitalize a business. 

There are a couple reasons to do this; business thrives on an anti-anonymity principle, and they probably reused the same payment key because that makes it simple for all the investors to easily verify that all the other investors are "in."

Yes, but a payout from a miner pool normally goes to multiple users instead of one, right?

Hm, didn't know that. Thanks for clearing that up  :)