Here's how you would handle filing taxes for your single-member LLC in this situation:

Even though your LLC has not made a profit, you still need to file a Schedule C with your personal 1040 tax return to report the business activity.

On Schedule C, report the $1,000 transfer from your personal account as "gross receipts.". This represents the money brought into the business.

Claim the $400 you spent on business expenses as deductions on Schedule C. Common deductible startup expenses include things like marketing, website development, supplies, etc. Keep records of all expenses.

The $1,000 transfer and $400 in expenses will net $600 in "net profit" on Schedule C, even though the business has not actually turned a profit yet.

You do not pay income tax on the $600 since the LLC is a "pass-through" entity. But you may owe self-employment taxes on the $600, which help fund Social Security and Medicare.

Any losses from the business can offset other income and potentially be carried forward to future years as a net operating loss.

Be sure to also file any required state tax returns for your LLC.

The key is reporting all business financial activity through your individual return by filing a Schedule C each year, even during unprofitable periods. This keeps everything above board with the IRS.