Due to #BIP91, an economically-significant split seems quite a bit less likely. However, a large split is still possible if miners renege on BIP91, which wouldn't be very difficult for them to do.
Also, it seems that the #Bitcoin Cash (BCC) #fork will happen regardless on Aug 1, but everything I've seen leads me to believe that BCC will have very low value. Research and decide for yourself.
As a side-effect of BIP91, the risk of long reorganizations will be somewhat increased for the next month or so. This could cause confirmations on transactions to disappear more easily than otherwise, which could allow for double-spending. If you want to be about as safe as possible, you should wait for 30 confirmations before trusting incoming transactions.
Source:https://bitcointalk.org/index.php?topic=2017191.msg20354283#msg20354283