The North American Securities Administrators Association (NASAA) is cautioning investors to watch out for opportunistic investment scams.

“As we are seeing in Texas, natural disasters bring out the best in people, with neighbours helping neighbours. Unfortunately, we know from experience that disasters also can bring out the worst in people, particularly those seeking to profit from the misfortune of others,” says Mike Rothman, NASAA president and Minnesota Commissioner of Commerce, in a release. “Unsolicited investment offers seeking to capitalize on the aftermath of Hurricane Harvey should be approached with extreme caution.”

Read: Buffett expects hurricane’s effects to linger

In particular, Rothman urges investors to watch for unsolicited email, social media messages, crowdfunding pitches or telephone calls promoting investment pools or bonds to help storm victims, water-removal or purification technologies, electricity-generating devices and distressed real estate remediation programs. Scammers may also prey on storm victims who anticipate receiving large lump-sum insurance settlements.

NASAA also flags fraudulent charitable solicitations. “As with any charitable contribution, those who want to contribute to relief efforts should send contributions to only those charities with an established track record of making sure the donations get to the victims,” suggests Rothman.

Read: Don’t let clients fall for binary options fraud

Separately, NASAA is extending the examination enrollment windows for the NASAA Series 63, 65, and 66 examinations for candidates in counties and regions declared disaster areas by state or federal governments as a result of the storm.

People with an examination window due to expire between August 25, 2017 and September 22, 2017 will have their windows extended to November 6, 2017. NASAA may provide additional extensions as more information becomes available.

Read: Getting U.S.-licensed creates a client stream