Answer: The excess return on long-term corporate bonds has exceeded the excess return on long-term government bonds.
Explanation:
From the year 1926 - 2017, the excess return on long term corporate bonds has indeed exceeded the excess return on their government counterpart.
Excess return is the amount of return that a security gives over the risk free rate.
Government bonds provide returns at the risk free rate while corporate bonds have to provide at a rate higher than the risk free rate. This means that corporate bonds will therefore give more excess returns than comparative government bonds.