[pre-tax 401k] Getting more employer match by switching employers and over contributing

[koalawjy]

Hypothetically, say I switch from employer A to employer B in mid 2024. Both employers provide a 50% match and use different 401k platforms. So, technically, I can contribute 23k (the limit for 2024) to both platforms and therefore 46k in total and get the 50% match from both employers. Then, in my tax return, I admit I over-contributed 23k and pay regular income tax for that 23k. Of course, after I retire, I pay tax again withdrawing the 23k*1.5 and the growth from it. 

Comparing to contributing 0 via company B, the above scenario is favorable if the match I got from employer B (23k*50%) is greater than the tax for the 35k after retirement. This is quite likely true because the tax rate after retirement tends to be low. 

Is my understanding correct? 

[Vanessa A]

From the tax side, you would potentially be subject to double taxation on that money if not withdrawn before the tax filing deadline.  It is taxed both when you should have been taxed on it if not for the overcontribution and again when you get a distribution from it.  Also, generally, it takes more than a few months to vest in a plan, so the extra you received in matching funds could potentially be wiped away.