I fear this question may turn out to be off-topic, because it may come down to personal opinion. If so, my apologies, although I'd be interested to hear the opinions of members of this community.
On the one hand, no major dictionary lists stakehold as a word. This includes:
1. OED; 2. M-W; 3. Oxford (autocorrects to stakeholding); 4. American Heritage; 5. Collins; 6. Macmillan; 7. Cambridge; 8. Wiktionary; 9. Webster's New World College Dictionary, 4th ed. (the site searches that dictionary, as can be seen e.g. here); 10. Wordsmyth; 11. Webster's Revised Unabridged, 1913 ed.; 12. dictionary.com; 13. vocabulary.com; 14. Wordnik; 15. Infoplease; 16. OPTED; and 17. Free Dictionary.
On the other hand, a search in google books shows that stakehold, used as a noun, does appear in published literature. The number and context of its appearances is such that, to me, it seems unlikely that all of these appearances are mistakes. In other words, it seems to me that, in many cases, the word was used purposefully by very literate writers. Some examples:
- taking a stakehold in its future (here);
- interested parties should have a stakehold in conservation (here);
- a stakehold interest in education (here, though in this case it is possibly an adjective);
- a stakehold he shared with several other miners (here);
- the money was accordingly deposited in the hands of the defendant, as a stakehold (here);
- the whole idea is for us to get a stakehold in a significant number of small businesses (here);
- we will have people who have a stakehold in this Country (here);
- everybody in Mississippi knew it was a stakehold of beatniks and immorality. (here);
- to insure that K-12 education has a stakehold in the development... of the NREN (here);
- Maryam also acquired a stakehold of 60 per cent shares (here);
- to acquire a stakehold in a Japanese company (here);
- to compensate employees with a stakehold in the company (here);
- fortunately for those who have a stakehold in the Association (here);
- we are poised to have a stakehold in the PC market (here);
- they had a stakehold in it (here);
- those who had attained a stakehold in the state (here);
- recognition of a stakehold interest in the property (here);
- provide a stakehold in the assessment process (here. This is from the 2009 ed.; interestingly, as one can see in the link, stakehold was changed to stake in the 2010 ed.);
- something to have a stakehold in if you own a big corporation (here);
- as a stakehold against depreciation (here);
- 5% of the value of the stakehold (here);
- the stakehold was held liable for paying over (here);
- belts and chains for sending men up from the stakehold, or down from aloft (here);
- a collective entitlement known as a "stakehold" (here);
- upriver from it was Cambridge-on-Jordan, the stakehold of the chief legist (here);
In most cases above, one could replace stakehold by the dictionary-listed word stake (see esp. 18.). But in other cases, e.g. 23, the word means something different.
So, my question: should the usage of stakehold as a noun be considered acceptable in (a) formal writing? (b) informal writing and speech?
Obviously, this is a special case of a more general question of just how widespread should a word become before it becomes acceptable. This general question is likely impossible to answer; nevertheless, the particular case at hand might be more tractable.