US Department of Energy research aimed at co-optimizing fuels and engine performance identified several bioblendstocks that can improve fuel economy including an aromatic-rich hydrocarbon derived from woody biomass. This work supports an analysis of its large-scale deployment implying a production target of approximately 15 billion liters of bioblendstock for the supply of 57 billion liters of high-octane fuel by 2050. It simulates potential transition pathways to lignocellulosic feedstock market structures capable of supplying a mature biorefining industry at this scale. In the present absence of biorefineries, transitions are modeled via nonbiofuel feedstock markets, so-called companion markets. The resource distribution across several demand industries is simulated to determine biomass availability and price dynamics over time. Results indicate that the wood supply base is mainly influenced by traditional markets including housing and pulp and paper. The selected companion market of wood pellet combustion for heat and electricity generation is found to positively stimulate biomass mobilization, especially in the initial absence of biorefineries. Eventually, biorefineries are found to be able to out-compete the companion market. As such, they directly benefit from the processing (i.e., pelleting) capacity established to produce commodity-type intermediates for the companion market. We conclude that the amount of bioblendstock produced is directly related to the size of the companion market (and its pelleting capacity). An initially larger companion market generates up to 20 million dry tonnes of additional feedstock, equivalent to 27 commercial-scale biorefineries, or an additional production of 5 billion liters by 2050. Distinguishing between industry-specific feedstock preferences based on average biomass quality characteristics, this analysis goes beyond past research efforts that assume automatic fungibility across different feedstocks. Improving engine performance is a key driver for the promotion of low-carbon fuels derived from bioblendstocks. This analysis portrays feedstock market transition pathways for their large-scale deployment.