The 23 points of IQ mentioned in the Inc. article trace back to this study performed with only two test subjects and employing EEG biofeedback, not standard meditation techniques. The headline of the Inc. article is pure nonsense.
As far as a general positive effect on IQ , the most directly relevant peer-reviewed study I could find was this review, "The Cumulative Effects of Transcendental Meditation on Cognitive Function--a Systematic Review of Randomised Controlled Trials" published in 2003. While it found 107 studies related to this particular form of meditation (transcendental meditation or TM) only 10 were randomized and controlled trials. The results are not very convincing and may even suggest the opposite:
Of the 10 trials included, 4 reported large positive effects of TM on
cognitive function, four were completely negative, and 2 were largely
negative in outcome. All 4 positive trials recruited subjects from
among people favourably predisposed towards TM, and used passive
control procedures. The other 6 trials recruited subjects with no
specific interest in TM, and 5 of them used structured control
procedures. The association observed between positive outcome, subject
selection procedure and control procedure suggests that the large
positive effects reported in 4 trials result from an expectation
effect. The claim that TM has a specific and cumulative effect on
cognitive function is not supported by the evidence from randomised
As I discuss in a related question, there is other kinds of evidence to support other kinds of meditation may have cognitive benefits. But regarding the specific claim about IQ, it does not seem to be directly supported.