A number of different branched hydrocarbon compounds (formula I) having a star-like configuration (S) are prepared from renewable oils containing fatty acids or derivatives containing fatty acids. The branched hydrocarbon compounds may be isolated individually or in mixtures, and may be used as part of base oils, such as renewable base oils (RBOs). A process for preparing the branched hydrocarbon compounds of formula I involve conditions that favour a trimerisation reaction followed by hydrotreating conditions. The compounds of formula I may be made by catalytically treating renewable material in a process, and the compounds have desirable qualities relating to lubrication, cold flow as well as having a low Noack volatility.