He bet all his savings on that startup, but he really backed the wrong horse
I thought she would win the election, but it turns out I backed the wrong horse
Investing in that company seemed like a good idea at the time, but I fear I've backed the wrong horse
She supported him for the promotion, only to realize later that he wasn't the best candidate; she had backed the wrong horse
The coach chose a new strategy, but the team struggled, suggesting he might have backed the wrong horse
Many people believed the trend would continue, but they ultimately backed the wrong horse
He trusted his friend with the business deal, but his friend failed him, meaning he had backed the wrong horse
Trying to predict the stock market is like backing the wrong horse most of the time
She championed the new policy, but it proved to be unpopular, indicating she had backed the wrong horse
Don't get too attached to one outcome; you might find yourself backing the wrong horse
I thought he would win, but I backed the wrong horse.
It happens to the best of us. Better luck next time.
I hope so. This was quite a disappointment.
He backed the wrong horse with that risky investment
His investment choice proved to be a mistake
He chose poorly; it was a bad decision