To summarize some of the reasons we believe this are about 90% of our net sales are generated by proprietary products and over three-quarters of our net sales come from products for which we believe we are the sole-source provider.
We have a little over $4.5 billion as of this quarter -- as of the end of this quarter.
Absent any capital market activity or other disruptions, we should have about $4.8 billion cash by the end of September fiscal year.
On the divestiture front, during Q3, we completed the sale of three less proprietary businesses for about $240 million.
For the first roughly 18 months, Kevin and his team successfully integrated Esterline Technologies, by far, the largest and most complicated acquisition in our history.
For the second roughly 18 months, Kevin and his team dealt with the unprecedented COVID-19-generated downturn in our largest market, the commercial aerospace market.
In our business, we saw another quarter of sequential improvement in commercial aftermarket revenues with total commercial aftermarket revenues up 6% over Q2.
In the commercial market, which typically makes up 65% of our revenue, we will split our discussion into OEM and aftermarket.
Our total commercial OEM revenue increased approximately 1% in Q3 compared with Q3 of the prior year.
Sequentially, both Q3 revenue and bookings improved approximately 10% compared to Q2.
Total commercial aftermarket revenues increased by approximately 33% in Q3 when compared to prior-year Q3.
Sequentially, total commercial aftermarket revenues grew approximately 6% in Q3.
Now, let me speak about our defense market, which traditionally is at or below 35% of our total revenue.
The defense market revenue, which includes both OEM and aftermarket revenues, grew by approximately 12% in Q3 when compared with the prior-year period.
EBITDA as defined of about $559 million for Q3 was up 32% versus prior Q3.
EBITDA as defined margin in the quarter was approximately 45.9%.
We are still not in a position to issue formal guidance for the remainder of fiscal 2021.
We assume another steady increase in commercial aftermarket revenue in this last quarter of our fiscal year and expect full-year fiscal 2021 EBITDA margin roughly in the area of 44%, which could be higher or lower based on the rate of commercial aftermarket recovery.
Organic growth was positive 15% on the quarter.
We now anticipate a lower GAAP and cash tax rate in the range of 0% to 3%, revised downward from a previous range of 18% to 22% and an adjusted tax rate in the range of 18% to 20%.
On interest expense, we still expect the full-year charge to be $1.06 billion.
Free cash flow, which we traditionally define at TransDigm as EBITDA as defined less cash interest payments, capex and cash taxes, was roughly $305 million.
And in line with our prior guidance on free cash flow, we still expect this metric to be in the $800 million to $900 million area for our fiscal '21 and likely at the high end of this range.
We ended the third quarter with $4.5 billion of cash, up from $4.1 billion at last quarter end.
And finally, our Q3 net debt to LTM EBITDA ratio was 7.6 times, down from 8.2 times at last quarter end.

Summary:
We are still not in a position to issue formal guidance for the remainder of fiscal 2021.