This paper investigates the multipath attenuation benefits and multipath spreading drawbacks of cooperative GNSS vector tracking in reference to conventional, single-receiver vector tracking. The study is conducted with a single reflection multipath model at the signal tracking correlator level. The algorithm is outlined as an EKF that relies on discriminators generated from the correlators for navigation corrections. Analytical and Monte-Carlo simulation results indicate that cooperation reduces code-based multipath error on a receiver by roughly 60%, in comparison to standalone processing, with 0% multipath spread to other receivers when several open sky receivers are employed. In the case when collaborating receivers experience correlated multipath errors, cooperative positioning is degraded with unbounded growth as more affected receivers are employed. GPS experimental results from a five-receiver group are presented and demonstrate the trade-off described by the numerical studies.