Here's a start for you:
Numerous PRs (and sometimes NRs) during which massive amounts of shares trade and the SP does very little and in many cases goes down (as those paid off dump their shares). If after numerous 'great news' items come out the SP still lags, probably a scam.
NR = item related to actual company operations - eg: earnings.
PR = (usually more numerous) items that may help the company in the future but are near impossible to verify - eg: an 'agreement' with a virtual unknown/company in a foreign country; marketing campaign on late nite TV (as opposed to being on Oprah); new management whom you cant track down a past of; many, many more.
Bottom line: NRs are businsess specific and usually few. PRs can be anything under the sun and are usually 'gigantic!' in nature, lol.
Not foolproof by any means but something to keep in mind.
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