Bitcoin (BTC)

Imagine a global currency that no single government or bank controls, with a supply that can never be inflated. That's the idea behind Bitcoin — and it's been running nonstop since January 2009.

Bitcoin was the first cryptocurrency to solve a tricky problem: how do you send money over the internet without trusting a middleman? The answer was proof-of-work consensus, where a decentralized network of computers validates every transaction on a public ledger anyone can inspect.

What makes Bitcoin scarce is simple math. Only 21 million coins will ever exist, and the rate of new coins entering circulation gets cut in half roughly every four years (an event called a "halving"). This built-in scarcity is a big reason people compare it to digital gold.

Since its early days as a niche experiment, Bitcoin has hit some major milestones — surpassing $1 trillion in market cap, becoming legal tender in El Salvador, and getting spot ETF approval in the US in 2024. Institutions, corporations, and even sovereign wealth funds now hold it.

If you're tracking Bitcoin in your portfolio, there are a few quirks to be aware of. It trades 24/7 across hundreds of exchanges with slightly different prices. You might hold some on an exchange, some on a hardware wallet, and maybe a bit in a mobile app. Pulling all of that together into one clear picture — especially for cost basis and tax reporting — is where a good portfolio tracker earns its keep.