Angel investors sign up for risk. That’s part of the game. What really gets them frustrated, though, is being sold unreasonable financial projections and valuations.

Nearly one in two angel investors surveyed by Worthworm, a Scottsdale, Ariz.-based startup valuation company, reported having regretted an investment decision they made this year. The small-sample survey of 100 angel investors was conducted in July by market research firm OnePoll.

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Of those angel investors who regretted an investment, almost half report that the problem was pie-in-the-sky financials -- entrepreneurs telling them that their company was going to be worth more than it was or that it would make more money than it ended up making.

To get an angel on board -- and keep him or her happy -- entrepreneurs need to have well thought out financial valuations and revenue projections they can deliver on.

“Our research clearly shows that angels believe the majority of entrepreneurs do not do their homework before stepping through the door,” says Alan Lobock, a co-founder of Worthworm, in a statement. “It is imperative that they put themselves in the investor’s shoes and prove that they can efficiently scale.”

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Only a small percentage of angel investors say they are in the startup investing game for the pure thrill of it. Most angels say they are looking to either diversify their portfolio or are attracted by the potential for a high reward on their investment.

In addition to wanting well-researched and reasonable financial projections, angel investors' other top concerns when deciding where to lay their financial bets also include having a demonstrable sustainable competitive advantage and relevant previous experience on the resumes of the startup team.

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