~Are there private individuals who own and posses such amount of Bitcoin?
There are, especially pioneers. Also there are publicly known Bitcoin whales like
Micree Zhan - is the Co-Founder of the Bitcoin mining company, Bitmain Technologies. Zhan is rumored to own the second largest wealth of Bitcoin. Zhan currently lives in Beijing.
Chris Larsen - is one of the early trailblazers of cryptocurrency. Founder and former CEO of Ripple, Larsen is the second confirmed wealthiest Bitcoin billionaire. Despite his recent criticisms of the cryptocurrency industry, Larsen is estimated to be the wealthiest person to build his entire fortune on crypto. His net worth is estimated to be over $6 billion.
Changpeng Zhao - When you found one of the largest cryptocurrencies exchanges in the world, it would make sense that you are also one of the leaders in the Bitcoin space. Changpeng Zhao founded Binance in 2017 after spending years working on Wall Street. Zhao has a large online presence, and has become popular for it.
Zhao continues to be a thought leader in the crypto world, with his own cryptocurrency now the third largest. Zhaos net worth is estimated to be around $1.9 billion, almost all of which from cryptocurrencies, primarily Bitcoin.
Source:
https://blog.coinsource.net/who-owns-the-most-bitcoin/~Why will one posses such amount as an Individual?
They are people who have insight and belief that Bitcoin will be adopted and will grow in price. They are businessmen or entrepreneurs, investors that wanted to take advantage of the potential profit Bitcoin offers.
~Are there any consequences to this?
In every action there is always a reaction, definitely, there will be consequences to their action, one of example is BIR pursuing them for crypto taxes, possible huge money lost if Bitcoin fail. ( But it is doing great atm)