On 1 August 2017, Bitcoin ledger split into 2, the original ledger (BTC) and Bitcoin Cash ledger (BCH).
If you own Bitcoin on the split, you own both BTC and BCH after the hard fork (assuming you hold private keys and not held-in-trust by a web wallet or exchange).
Both BTC and BCH is traded at different value.
BTC was traded at approximately 2860 USD at the time of split, where as BCH was traded at approximately 293 USD at the time of split.
That means in your hand, the value you hold in hand is increased at 10%.
In normal stock market, it is similar like the company is issuing a bonus share issue of 1 for every 10 shares.