What app/software do you recommend for consolidating several Quickbooks files into one for a consolidated PnL?

Hi serena-hamilton-,

Welcome to Community!  QuickBooks Online Advanced has the feature you need to combine reports from multiple companies, using Spreadsheet Sync.  You can upgrade your current subscription, if you're not currently subscribed to QuickBooks Online Advanced, by following this link.  In addition, you can review other QuickBooks compatible apps here. 

Feel free to reach back out if you have other questions.  We'd be happy to help!

@serena-hamilton- 

Explore a BI app

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