# Home **Balancer** is an automated **portfolio manager**, **liquidity provider**, and **price sensor**. Balancer turns the concept of an index fund on its head: instead of a paying fees to portfolio managers to rebalance your portfolio, you collect fees from traders, who rebalance your portfolio by following arbitrage opportunities. Balancer is based on an [N-dimensional invariant surface](https://balancer.finance/whitepaper/) which is a generalization of the constant product formula described by Vitalik Buterin and proven viable by the popular Uniswap dapp. {% file src="" %} Balancer Whitepaper {% endfile %}