My profit and loss for January shows stock shrinkage as I mistakenly categorized my stock as inventory rather than non inventory. Can I alter this?

Welcome to the Community, and thank you for choosing QuickBooks Online, @farm-millhouse-g.

I'll give an overview about updating the income account of your products. 

Updating the income account can only be done with non-inventory or service items. For accounting purposes, we're unable to do it on inventory items. 

If you've used non-inventory or service items on your sales receipts, all you have to do is toggle the income account again. 

There will be a box called Also update this account in historical transactions. You'll want to check it to recategorize your sales receipts under the correct income account. 

To toggle the income account: 

1. Go to the Products and services page again.
2. Find the service or non-inventory item, then click Edit. 
3. Change the income account to a different one.
4. Click Save and close. 
5. Open the item again.
6. Change the income account to the correct one.
7. Check the Also update this account in historical transactions box.
8. Click Save and close. 
   
   

If you've used inventory items on your sales receipts, the best way to handle this is to delete and recreate them. 

Our engineers might develop a way to do update the accounts on historical inventory-related transactions. Stay tuned for updates from our newsletters and in-product notifications. 

If you need help managing other transactions or running reports, feel free to browse topics from our Help Articles page.

Please tag me (@Jovychris_A) if you have more questions about QuickBooks Online. I'll get back to your post and help you more. Have a nice day!