Why does the first reduce not work but the second does?

(reduce (fn [{:keys [minimum maximum]} new-number]
          {:minimum (if (and minimum (< new-number minimum))
                      new-number
                      minimum)
           :maximum (if (and maximum (> new-number maximum))
                      new-number
                      maximum)})
        {}
        [5 23 5004 845 22])

(reduce (fn [{:keys [minimum maximum]} new-number]
          {:minimum (if (and minimum (> new-number minimum))
                      minimum
                      new-number)
           :maximum (if (and maximum (< new-number maximum))
                      maximum
                      new-number)})
        {}          ;; <---- The new argument!
        [5 23 5004 845 22])

The first reduce returns nil as the values to the keys; the second reduce works as expected. Why?